Sample records for recover heavy metals

Aluminum smelter plants employ Hall-Heroult electrolysis cells for electrolysis of molten cryolite to recover aluminum metal by electrolysis. These cells use carbon cathode blocks as a lining material inside. At the end of service life of the cells, pot lines are discarded and new carbon blocks are laid for fresh charging. These used carbon cathode blocks, known as spent pot liners, are heavily infested with toxic elements such as fluoride, cyanide, alkali, etc. Therefore, their disposal in open field poses great environmental risk. A simple process has been developed for decontamination of these spent pot liners and to recover its carbon value. The experiments indicated that this carbon, in the form of fine powder (around 20 micron in size) can absorb toxic elements like heavymetals, dyes, oils, etc. to a great extent and thus can be used for mitigating environmental pollution occuring due to various toxic wastes. PMID:19552074

Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavymetals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavymetals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides. PMID:26054963

A major product recovered from the processing and recycling of construction and demolition (C&D) debris is screened soil, also referred to as fines. A proposed reuse option for C&D debris fines is fill material, typically in construction projects as a substitute for natural soil....

Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

A process is described of recovering alkali metal vapor by sorption on activated alumina, activated carbon, dehydrated zeolite, activated magnesia, or Fuller's earth preheated above the vaporization temperature of the alkali metal and subsequent desorption by heating the solvent under vacuum. (AEC)

This patent describes a method for recoveringmetal from a waste stream to render the waste stream suitable for discharge. It comprises passing a waste stream comprised of heavymetal salts in dilute solution into a cathode chamber of an anion exchange membrane delineated electrolytic cell, wherein the metals are selected from the group having a standard reduction potential more negative than that of hydrogen in the electromotive force series and the heavymetal ion concentration of the solution is less than about 10,000 parts per million of dissolved material; subjecting the waste stream to high current density electrolysis at up to about 25 volts to enhance the controlled regular formation of a noncompressible metal hydrous oxide crystalline precipitate in the cathode chamber; separating the precipitate from the waste stream; and splitting the clarified liquid waste stream so that a portion of the clarified liquid waste stream is discharged and a portion is returned downstream for commingling with the metal ion-containing waste stream for further treatment.

In a process for hydrocracking heavy carbonaceous materials by contacting such carbonaceous materials with hydrogen in the presence of a molten metal halide catalyst to produce hydrocarbons having lower molecular weights and thereafter recovering the hydrocarbons so produced from the molten metal halide, an improvement comprising injecting into the spent molten metal halide, a liquid low-boiling hydrocarbon stream is disclosed.

A process is provided for removing heavymetal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavymetals removed from the heavy oils can be recovered from the spent sand for other uses.

Discusses the advantages, both functional and economic, of using a standing-seam metal roof in both new roof installations and reroofing projects of educational facilities. Structural versus non-structural standing-seam roofs are described as are the types of insulation that can be added and roof finishes used. (GR)

Biological processes have been used for thousands of years to make cheese, wine, and beer. During the past few hundred years these processes have been employed to process sewage. Increasingly, microbes are being used to clean up a wide variety of toxic chemical wastes that have been dumped into the environment. Scientists are currently examining the possible use of microbes to detoxify naturally occurring toxic selenium-bearing water at the Kesterson Wildlife Refuge. The mining and minerals industries also use biological processes to remove impurities from ores, cut processing costs, and treat some metallic ores that previously were too difficult or too expensive to process by traditional methods. In this article, the term mining industry' applies to the extraction of ore whereas the term minerals industry' applies to processing the ore. Applications of biotechnology in the mining and minerals industries are expected to increase. The paper discusses the use of microbial leaching in the copper, uranium, gold, and manganese mining industries; treatments of mine wastes; the treatment of cyanide solution, and research into bioleaching, biosorption, and genetic engineering.

Certain heavymetals are required, as trace elements for normal cellular functions. However, heavymetals are toxic to cells once their levels exceed their low physiological values. The toxicity of heavymetals on microorganisms, and on animals has been well-documented. These interactions may induce the alteration of the primary as well as secondary structures of the DNA and result in mutation(s). The present communication reports the results in determining the mutagenicity and carcinogenicity of ten heavymetals commonly found in polluted areas by using the Salmonella/mammalian-microsome mutagenicity test.

A method is described for recoveringmetals from metals-containing wastes, and vitrifying the remainder of the wastes for disposal. Metals-containing wastes such as circuit boards, cathode ray tubes, vacuum tubes, transistors and so forth, are broken up and placed in a suitable container. The container is heated by microwaves to a first temperature in the range of approximately 300--800 C to combust organic materials in the waste, then heated further to a second temperature in the range of approximately 1,000--1,550 C at which temperature glass formers present in the waste will cause it to melt and vitrify. Low-melting-point metals such as tin and aluminum can be recovered after organics combustion is substantially complete. Metals with higher melting points, such as gold, silver and copper, can be recovered from the solidified product or separated from the waste at their respective melting points. Network former-containing materials can be added at the start of the process to assist vitrification. 2 figs.

A method for recoveringmetals from metals-containing wastes, and vitrifying the remainder of the wastes for disposal. Metals-containing wastes such as circuit boards, cathode ray tubes, vacuum tubes, transistors and so forth, are broken up and placed in a suitable container. The container is heated by microwaves to a first temperature in the range of approximately 300-800.degree. C. to combust organic materials in the waste, then heated further to a second temperature in the range of approximately 1,000-1,550.degree. C. at which temperature glass formers present in the waste will cause it to melt and vitrify. Low-melting-point metals such as tin and aluminum can be recovered after organics combustion is substantially complete. Metals with higher melting points, such as gold, silver and copper, can be recovered from the solidified product or separated from the waste at their respective melting points. Network former-containing materials can be added at the start of the process to assist vitrification.

A method for recoveringmetals from metals-containing wastes, and vitrifying the remainder of the wastes for disposal. Metals-containing wastes such as circuit boards, cathode ray tubes, vacuum tubes, transistors and so forth, are broken up and placed in a suitable container. The container is heated by microwaves to a first temperature in the range of approximately 300.degree.-800.degree. C. to combust organic materials in the waste, then heated further to a second temperature in the range of approximately 1,000.degree.-1,550.degree. C. at which temperature glass formers present in the waste will cause it to melt and vitrify. Low-melting-point metals such as tin and aluminum can be recovered after organics combustion is substantially complete. Metals with higher melting points, such as gold, silver and copper, can be recovered from the solidified product or separated from the waste at their respective melting points. Network former-containing materials can be added at the start of the process to assist vitrification.

Certain heavymetals are required, as trace elements for normal cellular functions. However, heavymetals are toxic to cells once their levels exceed their low physiological values. The toxicity of heavymetals on microorganisms, on plants and on animals has been well-documented. These interactions may induce the alteration of the primary as well as secondary structures of the DNA and result in mutation(s). Though the rec assay with Bacillus subtilis and the reversion assay with Escherichia coli were used to assess the mutagenicity of some heavymetals, the present communication reports the results in determining the mutagenicity and carcinogenicity of ten heavymetals commonly found in polluted areas by using the Salmonella/mammalian-microsome mutagenicity test.

Recovering valuable metals such as Si, Ag, Cu, and Al has become a pressing issue as end-of-life photovoltaic modules need to be recycled in the near future to meet legislative requirements in most countries. Of major interest is the recovery and recycling of high-purity silicon (> 99.9%) for the production of wafers and semiconductors. The value of Si in crystalline-type photovoltaic modules is estimated to be -$95/kW at the 2012 metal price. At the current installed capacity of 30 GW/yr, the metal value in the PV modules represents valuable resources that should be recovered in the future. The recycling of end-of-life photovoltaic modules would supply > 88,000 and 207,000 tpa Si by 2040 and 2050, respectively. This represents more than 50% of the required Si for module fabrication. Experimental testwork on crystalline Si modules could recover a > 99.98%-grade Si product by HNO3/NaOH leaching to remove Al, Ag, and Ti and other metal ions from the doped Si. A further pyrometallurgical smelting at 1520 degrees C using CaO-CaF2-SiO2 slag mixture to scavenge the residual metals after acid leaching could finally produce > 99.998%-grade Si. A process based on HNO3/NaOH leaching and subsequent smelting is proposed for recycling Si from rejected or recycled photovoltaic modules. Implications: The photovoltaic industry is considering options of recycling PV modules to recovermetals such as Si, Ag, Cu, Al, and others used in the manufacturing of the PV cells. This is to retain its "green" image and to comply with current legislations in several countries. An evaluation of potential resources made available from PV wastes and the technologies used for processing these materials is therefore of significant importance to the industry. Of interest are the costs of processing and the potential revenues gained from recycling, which should determine the viability of economic recycling of PV modules in the future. PMID:25122953

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-building capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavymetals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. 115 refs., 7 figs., 3 tabs.

Decontamination of heavymetals-polluted soils remains one of the most intractable problems of cleanup technology. Currently available techniques include extraction of the metals by physical and chemical means, such as acid leaching and electroosmosis, or immobilization by vitrification. There are presently no techniques for cleanup which are low cost and retain soil fertility after metals removal. But a solution to the problem could be on the horizon. A small but growing number of plants native to metalliferous soils are known to be capable of accumulating extremely high concentrations of metals in their aboveground portions. These hyperaccumulators, as they are called, contain up to 1,000 times larger metal concentrations in their aboveground parts than normal species. Their distribution is global, including many different families of flowering plants of varying growth forms, from herbaceous plants to trees. Hyperaccumulators absorb metals they do not need for their own nutrition. The metals are accumulated in the leaf and stem vacuoles, and to a lesser extent in the roots.

The capacity of Acidithiobacillus thiooxidans DMS 11478 to recover the heavymetals contained in the residue obtained from the CARON process has been evaluated. Different bioreactor configurations were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor leaching and column leaching). In the two-stage system, 46.8% Co, 36.0% Mg, 26.3% Mn and 22.3% Ni were solubilised after 6h of contact between the residue and the bacteria-free bioacid. The results obtained with the stirred-tank reactor and the column were similar: 50% of the Mg and Co and 40% of the Mn and Ni were solubilised after thirty one days. The operation in the column reactor allowed the solid-liquid ratio to be increased and the pH to be kept at low values (<1.0). Recirculation of the leachate in the column had a positive effect on metal removal; at sixty five days (optimum time) the solubilisation levels were as follows: 86% Co, 83% Mg, 72% Mn and Ni, 62% Fe and 23% Cr. The results corroborate the feasibility of the systems studied for the leaching of metals from CARON process residue and these methodologies can be considered viable for the recovery of valuable metals. PMID:21466919

The invention relates generally to a process for recoveringmetals from an aqueous metal-bearing solution and, more particularly, to a process which utilizes metalloproteins immobilized on an insoluble support to remove metal ions such as the main group, transition, lanthanide, and actinide ions from the aqueous metal-ion bearing solution.

Lead recycling has many benefits. For example, it provides an alternative to virgin lead, thereby avoiding the environmental impacts of primary lead smelting. In addition, as with other secondary metal operations, it consumes less energy at a lower cost than primary production. An emerging process has been evaluated in which these attributes are leveraged to process refractory precious metals ores. Direct cyanidation of refractory gold and silver ore yields poor gold and silver recoveries. In fact, some ores are simply not amenable to direct cyanidation. The process described in this paper consists of smelting lead-bearing material together with argentopyrite concentrate that contains precious metals. Sodium carbonate is used as a fluxing agent and scrap iron is used as a reductant. The reaction product is molten lead bullion enriched with the precious metals. Smelting recoveries of both silver and gold can be as high as 98%.

Plants have been proposed as a bioremediation tool to help remove toxic heavymetals from contaminated land and water. However, little is known about how plants take up heavymetals from the soil and transport them to different parts of the plant. An important long term goal is t...

The research program was initiated with the objective of evaluating a new process, the sulfide precipitation of heavymetals from industrial wastewaters. The process was expected to effect a more complete removal of heavymetals than conventional lime processing because of the mu...

This invention relates to a separation means and method for enriching a hydrogen atmosphere with at least one heavy hydrogen isotope by using a solid titaniun alloy hydride. To this end, the titanium alloy hydride containing at least one metal selected from the group consisting of vanadium, chromium, manganese, molybdenum, iron, cobalt and nickel is contacted with a circulating gaseous flow of hydrogen containing at least one heavy hydrogen isotope at a temperature in the range of -20.degree. to +40.degree. C and at a pressure above the dissociation pressure of the hydrided alloy selectively to concentrate at least one of the isotopes of hydrogen in the hydrided metal alloy. The contacting is continued until equilibrium is reached, and then the gaseous flow is isolated while the temperature and pressure of the enriched hydride remain undisturbed selectively to isolate the hydride. Thereafter, the enriched hydrogen is selectively recovered in accordance with the separation factor (S.F.) of the alloy hydride employed.

Chalcopyrite (CuFeS{sub 2}) is one of the most abundant copper-bearing minerals in the U.S. Oxidative leaching and smelting and refining are the most common methods used for recovering copper from chalcopyrite. One of the problems associated with oxidative leaching is the formation of an elemental sulfur product layer around the unreacted chalcopyrite core. The sulfur coating slows the reaction by inhibiting both the diffusion of the oxidant to the unreacted core, and the diffusion of the copper and iron species to the bulk solution. Another problem with leaching is that the iron and copper are oxidized simultaneously. Both appear in the bulk solution in their most oxidized states. The direct electrodissolution of copper sulfide ore slurries could reduce the number of steps involved in the copper recovery process, possibly leading to significant reductions in energy consumption and operating costs. The potential application of electrodissolution processes in hydrometallurgy has been reviewed. This paper reviews investigations of the electrochemical dissolution of chalcopyrite, digenite (Cu{sub 1.8}S), chalcocite (Cu{sub 2}S) and covellite (CuS).

This patent describes a method to recovermetals from flue dust generated in an electric arc furnace, the method comprising: charging pelletized or powder flue dust into an electric induction furnace between induction susceptors; sealing of the furnace top to prevent entry of air; injecting natural gas through the bottom of the electric induction furnace as a solitary reducing agent; heating the charge by electromagnetic induction of the susceptors to provide reduction energy; recovering of heavymetals as a zinclead-cadmium alloy in a condenser at the top of the furnace; burning and scrubbing exiting gases in the condenser; and melting the remaining iron to produce steel and slag.

The long term goal of the funded research is to understand how heavymetals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavymetal uptake systems and thereby improve the ability of these plants to help clean up toxic metals from soils. A rate limiting step is using plant for bioremediation is the normally poor capacity of plants to concentrate toxic metals. Our interest in metal ion transport systems includes those for essential mineral nutrients such as molybdenum, copper, iron, manganese, as well as toxic metals such as cerium, mercury, cesium, cadmium, arsenic and selenium. Understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.

thereafter dies as a burnt-out, dim "white dwarf" . Stars with masses between 0.8 and 8 times that of the Sun are believed to evolve to AGB-stars and to end their lives in this particular way. At the same time, they produce beautiful nebulae like the "Dumbbell Nebula". Our Sun will also end its active life this way, probably some 7 billion years from now. Low-metallicity stars The detailed understanding of the "s-process" and, in particular, where it takes place inside an AGB-star, has been an area of active research for many years. Current state-of-the-art computer-based stellar models predict that the s-process should be particularly efficient in stars with a comparatively low content of metals ("metal-poor" or "low-metallicity" stars) . In such stars - which were born at an early epoch in our Galaxy and are therefore quite old - the "s-process" is expected to effectively produce atomic nuclei all the way up to the most heavy, stable ones, like Lead (atomic number 82 [2]) and Bismuth (atomic number 83) - since more neutrons are available per Iron-seed nucleus when there are fewer such nuclei (as compared to the solar composition). Once these elements have been produced, the addition of more s-process neutrons to those nuclei will only produce unstable elements that decay back to Lead. Hence, when the s-process is sufficiently efficient, atomic nuclei with atomic numbers around 82, that is, the Lead region, just continue to pile up. As a result, when compared to stars with "normal" abundances of the metals (like our Sun), those low-metallicity stars should thus exhibit a significant "over-abundance" of those very heavy elements with respect to Iron, in particular of Lead . Looking for Lead Direct observational support for this theoretical prediction would be the discovery of some low-metallicity stars with a high abundance of Lead. At the same time, the measured amounts of all the heavy elements and their relative abundances would provide very valuable information and

Lithium tritide (LiT) is extracted from molten lithium metal that has been exposed to neutron irradiation for breeding tritium within a thermonuclear or fission reactor. The extraction is performed by intimately contacting the molten lithium metal with a molten lithium salt, for instance, lithium chloride - potassium chloride eutectic to distribute LiT between the salt and metal phases. The extracted tritium is recovered in gaseous form from the molten salt phase by a subsequent electrolytic or oxidation step.

The accelerated rate of industrialization increases the demand for precious metals, while high quality natural resources are diminished quantitatively, with significant operating costs. Precious metals recovery can be successfully made from waste, considered to be secondary sources of raw material. In recent years, concerns and interest of researchers for more increasing efficient methods to recover these metals, taking into account the more severe environmental protection legislation. Precious metals are used in a wide range of applications, both in electronic and communications equipment, spacecraft and jet aircraft engines and for mobile phones or catalytic converters. The most commonly recovered precious metals are: gold from jewellery and electronics, silver from X- ray films and photographic emulsions, industrial applications (catalysts, batteries, glass/mirrors), jewellery; platinum group metals from catalytic converters, catalysts for the refining of crude oil, industrial catalysts, nitric acid manufacturing plant, the carbon-based catalyst, e-waste. An important aspect is the economic viability of recycling processes related to complex waste flows. Hydrometallurgical and pyrometallurgical routes are the most important ways of processing electrical and electronic equipment waste. The necessity of recovering precious metals has opened new opportunities for future research.

Magnetotactic bacteria (MTB), which can orient and migrate along a magnetic line of force due to intracellular nanosized magnetosomes, have been a subject of research in the medical field, in dating environmental changes, and in environmental remediation. This paper reviews the recent development of MTB as biosorbents for heavymetals. Ultrastructures and taxis of MTB are investigated. Adsorptions in systems of unitary and binary ions are highlighted, as well as adsorption conditions (temperature, pH value, biomass concentration, and pretreatments). The separation and desorption of MTB in magnetic separators are also discussed. A green method to produce metal nanoparticles is provided, and an energy-efficient way to recover precious metals is put forward during biosorption. PMID:22763846

The use of acidiphilic, chemolithotrophic iron- and sulfur-oxidizing microbes in processes to recovermetals from certain types of copper, uranium, and gold-bearing minerals or mineral concentrates is now well established. During these processes insoluble metal sulfides are oxidized to soluble metal sulfates. Mineral decomposition is believed to be mostly due to chemical attack by ferric iron, with the main role of the microorganisms being to reoxidize the resultant ferrous iron back to ferric iron. Currently operating industrial biomining processes have used bacteria that grow optimally from ambient to 50 degrees C, but thermophilic microbes have been isolated that have the potential to enable mineral biooxidation to be carried out at temperatures of 80 degrees C or higher. The development of higher-temperature processes will extend the variety of minerals that can be commercially processed. PMID:12142493

Microalgae account for most of the biologically sequestered trace metals in aquatic environments. Their ability to adsorb and metabolize trace metals is associated with their large surface:volume ratios, the presence of high-affinity, metal-binding groups on their cell surfaces, and efficient metal uptake and storage systems. Microalgae may bind up to 10% of their biomass as metals. In addition to essential trace metals required for metabolism, microalgae can efficiently sequester toxic heavymetals. Toxic heavymetals often compete with essential trace metals for binding to and uptake into cells. Recently, transgenic approaches have been developed to further enhance the heavymetal specificity and binding capacity of microalgae with the objective of using these microalgae for the treatment of heavymetal contaminated wastewaters and sediments. These transgenic strategies have included the over expression of enzymes whose metabolic products ameliorate the effects of heavymetal-induced stress, and the expression of high-affinity, heavymetal binding proteins on the surface and in the cytoplasm of transgenic cells. The most effective strategies have substantially reduced the toxicity of heavymetals allowing transgenic cells to grow at wild-type rates in the presence of lethal concentrations of heavymetals. In addition, the metal binding capacity of transgenic algae has been increased five-fold relative to wild-type cells. Recently, fluorescent heavymetal biosensors have been developed for expression in transgenic Chlamydomonas. These fluorescent biosensor strains can be used for the detection and quantification of bioavailable heavymetals in aquatic environments. The use of transgenic microalgae to monitor and remediate heavymetals in aquatic environments is not without risk, however. Strategies to prevent the release of live microalgae having enhanced metal binding properties are described. PMID:18161494

Highlights: ► This work focuses on demonstrating a new scaled up technology to separate the metallic and non-metallic fractions of PCBs. ► PCBs comminuted to <1 mm in size resulted in metallic grade concentration of 95% in some of the recovered products. ► Good separation was observed at 40 mm particle bed height due to the formation of well-structured global convection currents. ► The work reported here contributes to the development of a new approach to dry, fine particle separation. - Abstract: The need to recover and recycle valuable resources from Waste Electrical and Electronic Equipment (WEEE) is of growing importance as increasing amounts are generated due to shorter product life cycles, market expansions, new product developments and, higher consumption and production rates. The European Commission (EC) directive, 2002/96/EC, on WEEE became law in UK in January 2007 setting targets to recover up to 80% of all WEEE generated. Printed Wire Board (PWB) and/or Printed Circuit Board (PCB) is an important component of WEEE with an ever increasing tonnage being generated. However, the lack of an accurate estimate for PCB production, future supply and uncertain demands of its recycled materials in international markets has provided the motivation to explore different approaches to recycle PCBs. The work contained in this paper focuses on a novel, dry separation methodology in which vertical vibration is used to separate the metallic and non-metallic fractions of PCBs. When PCBs were comminuted to less than 1 mm in size, metallic grades as high as 95% (measured by heavy liquid analysis) could be achieved in the recovered products.

The industrial hygiene of heavymetals consists of recognition, evaluation, and control of exposures in the occupational environment. Several of these metals have been in use since ancient times. Reports of health effects and poisonings from overexposures also have a long history. This report discusses the industrial hygiene of the heavymetals, lead, cadmium, mercury, and manganese.

The Cuprex™ metal extraction process produces cathode-grade copper using a hydrometallurgical process based on chloride leaching of sulfide ore concentrates. The process incorporates several novel steps to overcome the major problems associated with earlier chloride-based processes, including mild leaching conditions using ferric chloride as leachant and solvent extraction of copper usinga novel reagent. This produces a highly concentrated cupric chloride electrolyte from which cathode-grade copper is electrowon in the Metclor cell. The technical viability and robustness of the core technology have been proven in a series of large-scale pilot trials. More recent work has concentrated on supplementary processes to convert the copper powder product to an article of commerce and to recover valuable by-products. A fully integrated scheme is now being developed with updated cost estimates.

There is growing interest in processing and utilizing the red mud by-product of the Bayer process for alumina extraction from bauxite. This interest stems largely from the environmental impacts associated with red mud and the storage costs involved. Furthermore, complete utilization of the raw materials, in this case bauxite, meets an ecological concept while ensuring raw material conservation. To prepare this article, the authors perused approximately 100 patents and articles in order to provide a concise description of the methods of storing red mud and its uses as a flocculant or construction material and in other minor applications. Special attention has been given to the methods developed for recoveringmetals contained in the red mud.

To evaluate levels of essential (zinc and copper) and non-essential (mercury and cadmium) heavymetals, 34 species of organisms from different areas close to the Antarctic Peninsula were analysed. These included algae, filter-feeders, omnivorous invertebrates and vertebrates. Mercury was not detected, while cadmium was found in the majority of organisms analysed (detection limit was 0.05 ppm for both metals). The highest cadmium concentration was observed in the starfish Odontaster validus. Anthozoans, sipunculids and nudibranchs showed maximum levels of zinc, while the highest copper level was found in the gastropod Trophon brevispira. Mercury and cadmium levels in fishes were below the detection limit. Concentrations of essential and non-essential metals in birds were highest in liver followed by muscle and eggs. Cadmium and mercury levels in muscle of southern elephant seals were above the detection limit, whereas in Antarctic fur seals they were below it. The objective of the study was to gather baseline information for metals in Antarctic Ocean biota that may be needed to detect, measure and monitor future environmental changes. 46 refs., 7 figs., 8 tabs.

The main threats to human health from heavymetals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavymetals have been used by humans for thousands of years. Although several adverse health effects of heavymetals have been known for a long time, exposure to heavymetals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. Cadmium compounds are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. Many individuals in Europe already exceed these exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, and dental amalgam. The general population does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and

Heavymetals are among the most common pollutants found in the environment. Health problems due to the heavymetal pollution become a major concern throughout the world, and therefore, various treatment technologies such as reverse osmosis, ion exchange, solvent extraction, chemical precipitation, and adsorption are adopted to reduce or eliminate their concentration in the environment. Biosorption is a cost-effective and environmental friendly technique, and it can be used for detoxification of heavymetals in industrial effluents as an alternative treatment technology. Biosorption characteristics of various bacterial species are reviewed here with respect to the results reported so far. The role of physical, chemical, and biological modification of bacterial cells for heavymetal removal is presented. The paper evaluates the different kinetic, equilibrium, and thermodynamic models used in bacterial sorption of heavymetals. Biomass characterization and sorption mechanisms as well as elution of metal ions and regeneration of biomass are also discussed. PMID:25471624

The long term goal of the funded research is to understand how heavymetals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavymetal uptake systems and thereby improve the ability of t...

Studied differentiating characteristics of youth who prefer heavymetal music, worship music, and use music for vicarious release. Data for 275 secondary school students suggest that heavymetal music preference and worshipping is not related to suicidal risk when controlling for other suicide factors. Discusses findings in the context of…

Reports on data taken from the General Social Survey that found a link between "heavymetal" rock fanship and suicide acceptability. Finds that relationship becomes nonsignificant once level of religiosity is controlled. Heavymetal fans are low in religiosity, which contributes to greater suicide acceptability. (Author/JDM)

An electrochemical method of separating heavymetal values from a radioactive molten salt including Li halide at temperatures of about 500.degree. C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavymetal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavymetal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavymetals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

An electrochemical method of separating heavymetal values from a radioactive molten salt including Li halide at temperatures of about 500{degree}C. The method comprises positioning a solid Li-Cd alloy anode in the molten salt containing the heavymetal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavymetal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavymetals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

Fungi constitute a high proportion of the microbial biomass in soil.Being widespread in soil their large surface-to-volume ratio and high metabolic activity, fungi can contribute significantly to heavymetal dynamics in soil. At neutral pH heavymetals in soils tend to be immobilized to precipitation and/or absorption to cation exchange sites of clay minerals. In the acidic soils, metals are more mobile and enter food webs easier. Microbial production of acids and chelating agents can mobilize to toxic metals. Mobilization is often by uptake and intracellular accumulation of the heavy metlas, and in this way, the bioavailability of metals towards other organisms can be more reduced. Fungi were isolated from soils from Upper Silesia in Poland and belonged to widespread genera: Aspergillus, Cladosporium, Penicillium and Trichoderma. Fungi from different taxonomic groups differ greatly in their tolerance to heavymetals. This could be related to their wall structure and chemistry as well as biochemical and physiological characteristics of fungi. Localization of metals in fungal cells was studied using electron microscopy analysis. Metal biosorption in the cell wall can be complex as melanin granules. Fungal vacuoles have an important role in the regulation of the cytosolic concentration of metal ions, and may contribute to heavymetal tolerance.In polluted soils with heavymetals, fungal species composition can be changed and their physiological activity can be changed, too.

In this study, a new method for recoveringheavymetals from hazardous waste is introduced. The process is characterized by a separation of heavymetals and residues during the thermal treatment under a sub-stoichiometric atmosphere in a rotary kiln. After leaving the rotary kiln the separated heavymetals are precipitated in a hot gas ceramic filter. Using this technology, hazardous materials, both liquids and pasty hazardous waste containing heavymetals, can be treated and a product with a quasi-raw material condition can be formed. In contrast to current methods,the harmful substances should not be immobilized and disposed. In fact, a saleable product highly concentrated with heavymetals should be formed. During preliminary investigations with a solution containing sodium chromate tetrahydrate, the process was tested in a pilot plant. Here,the separation of chromium could be demonstrated with leaching tests and characterization of the filter dust. Analysis concerning the disposability of the residues had not been carried out because only the process and the characteristic of the filter dust were in the centre of attention. PMID:17691119

This paper attempts to investigate the stabilization behaviours of heavymetals in ceramsite made from wastewater treatment sludge (WWTS) and drinking-water treatment sludge (DWTS). Leaching tests were conducted to find out the effects of sintering temperature, (Fe(2)O(3) + CaO + MgO)/(SiO(2) + Al(2)O(3)) (defined as F/SA ratios), pH, and oxidative condition. Results show that sintering exhibits good binding capacity for Cd, Cr, Cu, and Pb in ceramsite and leaching contents of heavymetals will not change above 1000 degrees C. The main crystalline phases in ceramsite sintered at 1000 degrees C are kyanite, quartz, Na-Ca feldspars, sillimanite, and enstatite. The main compounds of heavymetals are crocoite, chrome oxide, cadmium silicate, and copper oxide. Leaching contents of Cd, Cu, and Pb increase as the F/SA ratios increase. Heavymetals in ceramsite with variation of F/SA ratios are also in same steady forms, which prove that stronger chemical bonds are formed between these heavymetals and the components. Leaching contents of heavymetals decrease as pH increases and increase as H(2)O(2) concentration increases. The results indicate that when subjected to rigorous leaching conditions, the crystalline structures still exhibit good chemical binding capacity for heavymetals. In conclusion, it is environmentally safe to use ceramsite in civil and construction fields. PMID:20219229

Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavymetals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavymetal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavymetal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavymetals. PMID:1227849

Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavymetals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavymetal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavymetal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavymetals. PMID:1227849

A method for removing heavymetals from effluent water is described comprising performing sequentially the following steps: (a) adding from 7-333 ppm of an anionic surfactant to the effluent water to provide coagulatable heavymetal ion; (b) adjusting the effluent water pH to within the range of 8 to 10, (c) providing from 10-200 ppm of a cationic coagulant to coagulate the heavymetal ion, (d) providing from 0.3 to 5.0 ppm of a polymeric flocculant whereby a heavymetal containing floc is formed for removal from the effluent water, and, (e) then removing the floc from the effluent water, wherein the anionic surfactant is sodium lauryl ether sulfate. The cationic coagulant is selected from the group consisting of diallyl dimethylammonium chloride polymer, epichlorohydrin dimethylamine polymer, ethylene amine polymer, polyaluminum chloride, and alum; and the flocculant is an acrylamide/sodium acrylate copolymer having an RSV greater than 23.

Heavymetals are natural constituents of the earth's crust, but indiscriminate human activities have drastically altered their geochemical cycles and biochemical balance. This results in accumulation of metals in plant parts having secondary metabolites, which is responsible for a particular pharmacological activity. Prolonged exposure to heavymetals such as cadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Molecular understanding of plant metal accumulation has numerous biotechnological implications also, the long term effects of which might not be yet known. PMID:21713085

Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavymetals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavymetal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavymetals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavymetal binding.

To prepare measures for practical policy utilization and the control of heavymetals, hazard control related institutions by country, present states of control by country, and present states of control by heavymetals were examined. Hazard control cases by heavymetals in various countries were compared and analyzed. In certain countries (e.g., the U.S., the U.K., and Japan), hazardous substances found in foods (e.g., arsenic, lead, cadmium, and mercury) are controlled. In addition, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) recommends calculating the provisional tolerable weekly intake (PTWI) of individual heavymetals instead of the acceptable daily intake (ADI) to compare their pollution levels considering their toxicity accumulated in the human body. In Korea, exposure assessments have been conducted, and in other countries, hazardous substances are controlled by various governing bodies. As such, in Korea and other countries, diverse food heavymetal monitoring and human body exposure assessments are conducted, and reducing measures are prepared accordingly. To reduce the danger of hazardous substances, many countries provide leaflets and guidelines, develop hazardous heavymetal intake recommendations, and take necessary actions. Hazard control case analyses can assist in securing consumer safety by establishing systematic and reliable hazard control methods. PMID:24278603

A simple, fast, and inexpensive method was developed for detecting heavymetals via the ion mobility spectrometry (IMS) in the negative mode. In this method, Cl(-) ion produced by the thermal ionization of NaCl is employed as the dopant or the ionizing reagent to ionize heavymetals. In practice, a solution of mixed heavymetals and NaCl salts was directly deposited on a Nichrome filament and electrically heated to vaporize the salts. This produced the IMS spectra of several heavy-metal salts, including CdCl2, ZnSO4, NiCl2, HgSO4, HgCl2, PbI2, and Pb(Ac)2. For each heavymetal (M), one or two major peaks were observed, which were attributed to M·Cl(-) or [M·NaCl]Cl(-)complexes. The method proved to be useful for the analysis of mixed heavymetals. The absolute detection limits measured for ZnSO4 and HgSO4 were 0.1 and 0.05 μg, respectively. PMID:27321408

A literature review of bioaccumulation and toxicity of heavymetals is presented. The most common heavymetals studied were Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Ag, Cd, Sn, Hg, and Pb. The studies dealt with heavymetals in the environment, bioconcentration, toxicity, and detoxification of heavymetals. (JMT)

Innovative practices for treating waste streams containing heavymetals often involve technologies or systems that either reduce the amount of waste generated or recover reusable resources. With the land disposal of metal treatment residuals becoming less of an accepted waste man...

Innovative practices for treating waste streams containing heavymetals often involve technologies or systems that either reduce the amount of waste generated or recover reusable resources. ith the land disposal of metal treatment residuals becoming less of an accepted waste mana...

Stormwater sampling for colloidal and dissolved metals and organic carbon has been initiated at six outfalls draining locally-designated, nonindustrial land uses in Monmouth County, NJ. Of the heavymetals, only Cu and Zn were found in all samples, mostly in dissolved form. Large...

... or radioactively contaminated, except for silver. Only high grade nonradioactively contaminated silver should be reported to the precious metals pool. The Oak Ridge Operations Office is responsible...

Sewage sludges as well as ashes from waste incineration plants are known accumulation sinks of many elements that are either important nutrients for biological organisms (phosphorus, potassium, magnesium, etc.) or valuable metals when considered on their own in pure form (nickel, chrome, zinc, etc.); they are also serious pollutants when they occur in wild mixtures at localized anthropogenic end- of-stream points. Austria and many other countries have to import up to 90% of the material inputs of metals from abroad. These primary resources are becoming more expensive as they become more scarce and remaining deposits more difficult to mine, which is a serious concern for industrialized nations. Basic economic and strategic reasoning demands an increase in recycling activities and waste minimization. Technologies to recovermetals in a reasonable and economically relevant manner from very diffuse sources are practically non-existent or require large amounts of energy and chemicals, which pose environmental risks. On the other hand agriculture uses large volumes of mineral fertilizers, which are often sourced from mines as well, and thus are also subject to the same principle of finiteness and potential shortage in supply. These converted biological nutrients are taken up by crops and through the food chain and human consumption end up in sewage systems and in wastewater treatment plants in great quantities. The metabolized nutrients mostly do not return to agriculture, but due to contamination with heavymetals are diverted to be used as construction aggregates or are thermally treated and end up rather uselessly in landfills. The project BIO-ORE aimed to explore new pathways to concentrate metals from diluted sources such as sewage sludge and wastewater by using highly efficient biological absorption and transport mechanisms. These enzymatic systems from plants work with very little energy input. The process is called bioaccumulation and can be most effectively

Heavymetal contamination has become a worldwide problem through disturbing the normal functions of rivers and lakes. Sediment, as the largest storage and resources of heavymetal, plays a rather important role in metal transformations. This paper provides a review on the geochemical forms, affecting factors and remediation technologies of heavymetal in sediment. The in situ remediation of sediment aims at increasing the stabilization of some metals such as the mobile and the exchangeable fractions; whereas, the ex situ remediation mainly aims at removing those potentially mobile metals, such as the Mn-oxides and the organic matter (OM) fraction. The pH and OM can directly change metals distribution in sediment; however oxidation-reduction potential (ORP), mainly through changing the pH values, indirectly alters metals distribution. Mainly ascribed to their simple operation mode, low costs and fast remediation effects, in situ remediation technologies, especially being fit for slight pollution sediment, are applied widely. However, for avoiding metal secondary pollution from sediment release, ex situ remediation should be the hot point in future research. PMID:18547718

Complementary and alternative medications, including the use of herbal medications, have become quite popular in the USA. Yerberias are found throughout the southwest and specialize in selling Hispanic herbal products. The products sold in these stores are not regulated by any governmental agency. Previous reports have found Ayurvedic medications contain high levels of lead, mercury, and arsenic. The primary purpose of this study is to examine the prevalence of heavymetal contaminants sold at Yerberia stores in the southwest. Yerberias in the Phoenix, Arizona area were identified via search of an on-line search engine using the words "Yerberia Phoenix." Every second store was selected, and products were purchased using a standard script. The products were subsequently analyzed for mercury, lead, and arsenic. The main outcome is the prevalence of heavymetal content in over-the-counter "cold" medications purchased at a Yerberia. Twenty-two samples were purchased. One product contained pure camphor (2-camphone) and was subsequently not further analyzed. Of the 21 samples analyzed, lead was found in 4/21 (19.4 %). Arsenic and mercury were in 1/21 (4.8 %) each. Because two samples contained two heavymetals, the total prevalence of heavymetals was 4/21 (19.4). Heavymetal contaminants are commonly encountered in over-the-counter herbal "cold" medications purchased at Yerberias in the southwest. PMID:22562238

Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavymetal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavymetals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavymetals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavymetals toxicity in CVD. In this review, we will give a brief summary of heavymetals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed. PMID:21912545

The National Energy Conservation Policy Act of 1978 directs DOE to set targets for increased utilization of energy-saving recovered materials for certain industries. These targets are to be established at levels representing the maximum feasible increase in utilization of recovered materials that can be achieved progressively by January 1, 1987 and is consistent with technical and economic factors. A benefit to be derived from the increased use of recoverable materials is in energy savings, as state in the Act. Therefore, emhasis on different industries in the metals sector has been related to their energy consumption. The ferrous industry (iron and steel, ferrour foundries and ferralloys), as defined here, accounts for approximately 3%, and all others for the remaining 3%. Energy consumed in the lead and zinc segments is less than 1% each. Emphasis is placed on the ferrous scrap users, followed by the aluminum and copper industries. A bibliography with 209 citations is included.

Industrial wastes are a major source of soil and water pollution that originate from mining industries, chemical industries, metal processing industries, etc. These wastes consist of a variety of chemicals including phenolics, heavymetals, etc. Use of industrial effluent and sewage sludge on agricultural land has become a common practice in the world which results in these toxic metals being transferred and ultimately concentrate in plant tissues from water and the soil. The metals that get accumulated, prove detrimental to plants themselves and may also cause damage to the healths of animals as well as man. This is because the heavymetals become toxins above certain concentrations, over a narrow range. As a further matter, these metals negatively affect the natural microbial populations as well, that leads to the disruption of fundamental ecological processes. However, many techniques and methods have been advanced to clear the heavymetal polluted soils and waters. One important method is by removing heavymetals with the help of amino acids like L-Cysteine and L-Penicillamine. But also, economy of removal of pollutant heavymetals from soils and waters is a major concern. Present study helps in decreasing the cost for large-scale removal of heavymetals from polluted water by recovering the amino acid (L-Cysteine) after removal of nickel (Ni+2) at a fixed pH, by binding the Ni+2 with halloysite nanotubes(HNT), so that L-Cysteine can be reused again for removal of heavymetals.

Heavymetals are natural elements that generally occur in minute concentrations in the earth's crust. While some of these elements, in small quantities, are vital to life, most are harmful in larger doses. Various industrial and agricultural processes can result in dangerously high concentrations of heavymetals in our environment. Consequently, humans can be exposed to unsafe levels of these elements via the air we breathe, the water and food we consume, and the many products we use. During a two week study we collected numerous samples of sediments, water, food, and household items from around the San Francisco Bay Area that represent industrial, agricultural, and urban/residential settings. We analyzed these samples for Mercury (Hg), Lead (Pb), and Arsenic (As). Our goal was to examine the extent of our exposure to heavymetals in our daily lives. We discovered that many of the common foods and materials in our lives have become contaminated with unhealthy concentrations of these metals. Of our food samples, many exceeded the EPA's Maximum Contaminant Levels (MCL) set for each metal. Meats (fish, chicken, and beef) had higher amounts of each metal than did non-meat items. Heavymetals were also prevalent in varying concentrations in the environment. While many of our samples exceeded the EPA's Sediment Screening Level (SSL) for As, only two other samples surpassed the SSL set for Pb, and zero of our samples exceeded the SSL for Hg. Because of the serious health effects that can result from over-exposure to heavymetals, the information obtained in this study should be used to influence our future dietary and recreational habits.

Composting is one of the more efficient and environment friendly methods of solid waste disposal and has many advantages when compared with landfill disposal on which the UK and Ireland are currently heavily dependent. Composting is a very complicated process involving intensive microbial activity and the detailed mechanisms of the process have yet to be fully understood. Metal speciation information can provide an insight into the metal-microbial interaction and would help in the evaluation of the quality of compost. This would facilitate the exploitation of composts in remediation of heavymetal contaminated land. In this work a systematic approach to metal speciation in compost has been taken by applying the three-step method for operationally defined metal speciation of soils and sediments, developed by the European Commission's Standards, Measurement and Testing Programme to monitor the change in metal speciation with time (up to 106 days) for four different waste composting processes. The results have shown that in general metals become less available for the first extraction step as the composting process proceeds. This implies that composting tends to redistribute the metals from more labile forms to more fixed forms which may explain why the application of composts could be useful for with heavymetal contaminated land. There are exceptions to this trend and in some cases, certain metals appear to behave differently depending on the source of the compost. PMID:11993774

Highway stormwater runoff contains significantly higher concentrations of trace metals, particularly Pb, Zn, Cd, Cu, Cr, Fe, and Ni than the water samples from adjacent receiving water bodies. The metals associated with highway runoff tend to be detoxified by the organic content and chemical conditions of natural waters and sediments. Most of the metals are retained by the bottom sediments on a permanent basis if aerobic conditions and high redax-potential (Eh) values are maintained. Retention/detention ponds similar to the Maitland Pond site are very effective in nutrient and heavymetal removal from highway runoff.

The contamination of the environment with toxic metals has become a worldwide problem. Metal toxicity affects crop yields, soil biomass and fertility. Soils polluted with heavymetals pose a serious health hazard to humans as well as plants and animals, and often requires soil remediation practices. Phytoextraction refers to the uptake of contaminants from soil or water by plant roots and their translocation to any harvestable plant part. Phytoextraction has the potential to remove contaminants and promote long-term cleanup of soil or wastewater. The success of phytoextraction as a potential environmental cleanup technology depends on factors like metal availability for uptake, as well as plants ability to absorb and accumulate metals in aerial parts. Efforts are ongoing to understand the genetics and biochemistry of metal uptake, transport and storage in hyperaccumulator plants so as to be able to develop transgenic plants with improved phytoremediation capability. Many plant species are being investigated to determine their usefulness for phytoextraction, especially high biomass crops. The present review aims to give an updated version of information available with respect to metal tolerance and accumulation mechanisms in plants, as well as on the environmental and genetic factors affecting heavymetal uptake. The genetic tools of classical breeding and genetic engineering have opened the door to creation of 'remediation' cultivars. An overview is presented on the possible strategies for developing novel genotypes with increased metal accumulation and tolerance to toxicity. PMID:22542973

Microalgae are aquatic organisms possessing molecular mechanisms that allow them to discriminate non-essential heavymetals from those essential ones for their growth. The different detoxification processes executed by algae are reviewed with special emphasis on those involving the peptides metallothioneins, mainly the post transcriptionally synthesized class III metallothioneins or phytochelatins. Also, the features that make microalgae suitable organisms technologies specially to treat water that is heavily polluted with metals is discussed. PMID:16405948

Thermal enhanced oil recovery using geopressured-geothermal (GPGT) fluids is a unique concept for recoveringheavy and medium oils that are bypassed during conventional production processes. The successful implementation of this technology would provide an environmentally clean and less expensive method of thermal recovery as opposed to the burning of crude oil or natural gas used widely by industry at the present time. GPGT fluids are under high pressure in their parent reservoir and, when linked to shallow reservoirs by suitable plumbing, will provide a self-propelled method of heat transfer to a target reservoir existing at shallow depth. GPGT fluids will heat the reservoir as in conventional thermal enhanced oil recovery. This will reduce the residual oil saturation and lower the viscosity of the oil so that it can be moved more easily and in greater amounts. The method is similar to hot water flooding, and thus the basic technology already exists. Alworth field of the south Texas Mirando trend is proposed as a pilot site. The temperatures of the upper Wilcox GPGT fluids in this region range form 350 to 500F, and salinities in the range of 3600 to 70,000 mg/L. The pressures are from 800 to 3500 psia flowing well-head pressure. The target reservoirs for injection of the GPGT fluids are the upper Eocene Jackson and Yegua sandstones. These reservoirs contain an estimated four million bbl of heavy oil in place (18 API) of which at least one million bbl could be recovered by thermal enhanced oil recovery. An additional 1.5 billion bbl of oil is recoverable from the 87 fields within the Mirando trend. Run of the economic model on the Alworth field suggests that it will be economic.

USDA researchers are experimenting with plants that naturally scavenge heavymetals such as cadmium and zinc from the soil. Known as hyperaccumulators, the plants can store up to 2.5% of their dry weight in heavymetals in leaves without yield reductions. They can be grown, harvested, and dried. The dried material is then burned, and the metal ore can be recovered. As well as discussing the history of hyperaccumulators, this article focuses on the plant pennycress and work on improving its metal uptake.

Four bacteria, Bacillus cereus, B. subtilis, Escherichia coli, and Pseudomonas aeruginosa, were examined for the ability to remove Ag+, Cd2+, Cu2+, and La3+ from solution by batch equilibration methods. Cd and Cu sorption over the concentration range 0.001 to 1 mM was described by Freundlich isotherms. At 1 mM concentrations of both Cd2+ and Cu2+, P. aeruginosa and B. cereus were the most and least efficient at metal removal, respectively. Freundlich K constants indicated that E. coli was most efficient at Cd2+ removal and B. subtilis removed the most Cu2+. Removal of Ag+ from solution by bacteria was very efficient; an average of 89% of the total Ag+ was removed from the 1 mM solution, while only 12, 29, and 27% of the total Cd2+, Cu2+, and La3+, respectively, were sorbed from 1 mM solutions. Electron microscopy indicated that La3+ accumulated at the cell surface as needlelike, crystalline precipitates. Silver precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasm. Neither Cd2+ nor Cu2+ provided enough electron scattering to identify the location of sorption. The affinity series for bacterial removal of these metals decreased in the order Ag greater than La greater than Cu greater than Cd. The results indicate that bacterial cells are capable of binding large quantities of different metals. Adsorption equations may be useful for describing bacterium-metal interactions with metals such as Cd and Cu; however, this approach may not be adequate when precipitation of metals occurs. Images PMID:2515800

The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavymetals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavymetals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavymetal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions. PMID:22102792

The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavymetals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavymetals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavymetal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions. PMID:22102792

Sampling has been undertaken to determine the concentrations of heavymetals, both particle-associated and dissolved, in stormwater from several storm sewer outfalls in Monmouth County, NJ. This project is ongoing in concert with coordinated studies of pathogen and nutrient input...

Presents a literature review of heavymetals and related trace elements in the environment, covering publications of 1976-77. This review includes: (1) trace treatment in natural water and in sediments; and (2) bioaccumulation and toxicity of trace elements. A list of 466 references is presented. (HM)

Heavymetal tolerant and resistant strains of streptomycetes isolated from a former uranium mining site were screened for their superoxide dismutase expression. From the strains tolerating high concentrations of different heavymetals, one was selected for its tolerance of concentrations of heavymetals (Ni, Cu, Cd, Cr, Mn, Zn, Fe). This strain, Streptomyces acidiscabies E13, was chosen for the purpose of superoxide dismutase analysis. Gel electrophoresis and activity staining revealed only one each of a nickel (NiSOD) and an iron (FeZnSOD) containing superoxide dismutase as shown by differential enzymatic repression studies. The gene for nickel containing superoxide dismutase, sodN, was cloned and sequenced from this strain. The genomic sequence shows 92.7% nucleotide identity and 96.1% amino acid identity to sodN of S. coelicolor. Expression can be activated by nickel as well as other heavymetals and active enzyme is produced in media lacking nickel but containing copper, iron or zinc. Thus, the selected strain is well suited for further characterization of the enzyme encoded by sodN. PMID:17304620

OBJECTIVES: To discover, improve, understand the mechanisms and use naturally occurring bacteria to decontiminate in situ heavymetals from the soils, sediments and waters to protect human health and the environment.

Artificial wetlands have been operated successfully for treatment of municipal wastewater for a number of years at several locations in this country. However, the capability of these systems to treat heavymetal laden municipal wastewater had not previously been investigated. The...

Concentration (Cd, Pb, Zn, and Cu) in soil and wildlife at the Palmerton zinc smelter site in eastern Pennsylvania were determined 6 yr after zinc smelting was terminated in 1980. Levels of the four metals were higher in litter (01 and 02 horizon) than in soil (A1 horizon), and the metals were at or near levels when the smelters were still in operation. Levels of metals in sod weft highest at sites close to the smelters and decreased as distances from the smelters increased. The relation of decreasing amounts of metals in body tissues with increasing distance from the smelters also held true for amphibians and mammals. An exception to this relation was higher level of Cu in red-lacked salamanders (Plethodon cinereus) captured {approx}17 km downwind than those captured {approx}12 km downwind. Levels of Zn, Pb, and Co in liver, kidney, and muscle tissue of white-footed mice (Peromyscus leucopus) were not different (P >0.05) among sites. Cadmium in kidneys in white-footed mice exceeded 10 mg&& which is reportedly considered an indication of environmental contamination. Levels of Cd in kidneys and liver of white-tailed deer (Odocoileus virginianus) at Palmerton were five times higher than those for white-tailed deer collected 180 km southwest of Palmerton in southcentral Pennsylvania. The abnormal amounts of metals in the tissues of terrestrial vertebrates, and the absence or low abundance of wildlife at Palmerton indicated that ecological processes within 5 km of the smelters were markedly influenced 6 yr after zinc smelting was discontinued. 41 refs., 5 figs., 4 tabs.

The valuable gems in Sri Lanka are found from the sedimentary gem deposits in Ratnapura District, which are found as alluvial deposits some are about >50 m deep. Gem bearing gravel layer is taken out from the mine, washed by panning to recover the gem minerals in the heavy mineral fraction, is a common practice in the gem mining area. Gem bearing sediment layer is associated with different heavy minerals in which different trace metals as Co, Cr, Cu, Al, Zr, Pb and As also can be present. During panning, the sediment is washed away and the heavymetals attached to the sediments are released into the environment. Hence we studied the lability and bioavailability of arsenic and other heavymetals from the gem sediments. Sediment samples were collected from 15 small scale gem mines (3 soil layers- top, gem mineral layer and layer below gem bearing gravel layer), air dried and sieved to obtain <63μm fraction. Bioavailable, exchangeable and residual fractions were 0.01M CaCl2, 1M NaOAc, pH 8.2 and microwave digestion using HF, HNO3 and HClO4. Filtered samples were analyzed for As, Co, Zn, Mn, Cu, Ni, Pb and Fe using atomic absorption spectrophotometer (GBC 933AA). Total digestion results in different layers indicated that heavymetals show an increasing pattern with depth. About 4 gem bearing gravel layers were consist of high concentrations of Ni (>150 mg/kg), Cu (>150 mg/kg), Pb (>400 mg/kg), Zn (>600 mg/kg) and Co ions (>100 mg/kg). Arsenite in the gem sediments were low and recorded as <5mg/kg. Total arsenic analysis is under investigation. Highest concentrations for bioavailable and exchangeable (leach to water) metals were Fe>Co>Zn>Mn>Ni>Cu>Pb. Sediments from few gem pits showed considerably high concentrations of metals analyzed. In some places Fe, Ni, Cu, Zn reported high in bioavailable fractions 70, 25, 20, 10 mg/kg respectively. Mobilization of these metals may increase due to changes in the pH and the presence of other ions in the environment. High

Heavymetal is widely used in industries and presents as a problematic environmental pollution. Some heavymetals, especially lead and mercury, are well described for their occupational and environmental intoxication whereas the other minor heavymetals are less concerned. In this article, the author will present the details of occupational and environmental minor heavymetal intoxication. This review focuses mainly on aluminum, tin, copper, manganese, chromium, cadmium and nickel. PMID:20040969

Metal tolerance capacity of Salvinia natans, a metal hyperaccumulator, was evaluated. Plants were exposed to 10, 30 and 50 mg L⁻¹ of Zn, Cd, Co, Cr, Fe, Cu, Pb, and Ni. Plant biomass, photosynthetic efficiency, quantum yield, photochemical quenching, electron transport rate and elemental (%C, H and N) constitution remained unaffected in Salvinia exposed to 30 mg L⁻¹ of heavymetals, except for Cu and Zn exposed plants, where significant reductions were noted in some of the measured parameters. However, a significant decline was noted in most of the measured parameters in plants exposed to 50 mg L⁻¹ of metal concentration. Results suggest that Salvinia has fairly high levels of tolerance to all the metals tested, but the level of tolerance varied from metal to metal. PMID:23553503

Sites contaminated by heavymetals, such as industrial waste sites, create unwelcoming environments for plant growth. Heavymetals can have a wide range of toxic effects such as replacing essential elements or disrupting enzyme function. While some heavymetals are essential to plant nutrition at low concentrations, high concentrations of any…

The functional value of heavymetals in proto-cells was immense and involved critical roles in catalysis of molecular synthesis, translation, electrical neutrality and conduction, energy capture, cross-linking and precipitation (stabilizers of protective cell walls), and to a limited extent, osmotic pressure control. Metals must have modulated the evolutionary choices of the types of building blocks, such as ribose sugars as a constituent of RNA, or the the chirality and enantiopurity of many biomolecules. The formation of an enclosing membrane led to intracellular prokaryotic life (believed to have originated in an anaerobic environment) and much enhanced control over primary metabolism, the uptake and incorporation of heavymetals and the management of biomolecules (especially RNA, DNA and proteins) that were formed. Cells of the most primitive organisms (archaebacteria) reveal complex mechanisms designed specifically to deal with selective pressures from metal-containing environments including intra- and extra-cellular sequestration, exclusion by cell wall barrier, removal through active efflux pumps, enzymatic detoxification, and reduction in sensitivity of cellular targets to metal ions. Adaptation to metals using a variety of chromosomal, and transposon and plasmid-mediated systems began early in the evolution of life on Earth. Recent studies, however, show that the roles played by many heavymetals have changed over time. Divalent lead, for instance, has relinquished its unique catalytic role in the conversion of carbohydrates into ribose in the prebiotic world. The putative elements that dominated the primordial biochemistry were V, Mo, W, Co, Fe(II) and Ni; with the development of oxygenated atmosphere, these elements gave way to Zn, Cu and Fe(Ill) in their metabolic functions.

An electrochemical method is described for separating heavymetal values from a radioactive molten salt including Li halide at temperatures of about 500 C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavymetal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavymetal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavymetals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode. 3 figs.

In the paper, hydrothermal treatment (HT) of MSWI fly ashes was performed to stabilize and separate heavymetals. Influences of pre-treatment, types of ferric and/or ferrous additives, and subsequent heavymetal stabilization procedure by adding phosphate were investigated. The chemical stability of hydrothermal products was examined by solid waste extraction procedure with acetic acid buffer solution. Mineralogical investigation of selected hydrothermal product was carried out by XRD. FEGE SEM- -EDX was used to study the morphology and surface compositions of the ash particles. Experimental results revealed that HT process facilitated heavymetal exposure to leaching solution. FEGE SEM-EDX images revealed that fly ash particles were re-organized during hydrothermal process and that the minerals with special shapes and containing high levels of heavymetals were formed. A mild acid washing treatment with final pH around 6.20 could remove soluble heavymetals. Therefore, it may be a proper pre- or post-treatment method for fly ash particles for the purpose of reducing heavymetal contents. For the purpose of stabilizing heavymetals, the addition of ferric/ferrous salts in the HT process or phosphate stabilization after HT is recommended. The HT process may be applied to realize the environmentally sound management of MSWI fly ash or to recover and utilize MSWI fly ash. PMID:26100935

Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavymetals. The adsorption of heavymetals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (α) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (α) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(α 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavymetals seems to

Heavymetals are dense chemicals with dual biological role as micronutrients and intoxicants. A few hypersaline environmental systems are naturally enriched with heavymetals, while most metal-contaminated sites are a consequence of human activities. Numerous halotolerant and moderately halophilic Bacteria possess metal tolerance, whereas a few archaeal counterparts share similar features. The main mechanisms underlying heavymetal resistance in halophilic Bacteria and Archaea include extracellular metal sequestration by biopolymers, metal efflux mediated by specific transporters and enzymatic detoxification. Biotransformation of metals by halophiles has implications both for trace metal turnover in natural saline ecosystems and for development of novel bioremediation strategies. PMID:27279625

The environmental impact of heavymetals is reviewed. One significant source of emissions of heavymetals to air is waste incineration. Consumer batteries contributes significantly to this problem, as well as to heavymetal leakage to groundwater from landfill deposits. The situation in Sweden is used as an example to describe how the deposition from the atmosphere still is increasing the load of heavymetals, like mercury, cadmium and lead, in top soils and aquatic sediments. Critical factors and effect levels for Hg, Cd, Pb, Cu, Zn and As are discussed. Specific questions like mercury contents in present battery waste and heavymetal contents in new and future secondary batteries are addressed.

A comparison is made of soil and earthworm contamination by PCBs and heavymetals between a nature reserve and two sites conditioned by the addition of sewage sludge and compost. The tissues and gut content of the earthworms shows a higher PCB concentration than that of the surrounding soil and also a difference in the fingerprint of some single PCB compounds. Earthworms display a selective accumulation of cadmium and zinc in their tissues and gut content.

Separating urine from wastewater at the source reduces the costs of extensive wastewater treatment. Recovering the nutrients from urine and reusing them for agricultural purposes adds resource saving to the benefits. Phosphate can be recovered in the form of struvite (magnesium ammonium phosphate). In this paper, the behaviour of pharmaceuticals and heavymetals during the precipitation of struvite in urine is studied. When precipitating struvite in urine spiked with hormones and non-ionic, acidic and basic pharmaceuticals, the hormones and pharmaceuticals remain in solution for more than 98%. For heavymetals, initial experiments were performed to study metal solubility in urine. Solubility is shown to be affected by the chemical conditions of stored and therefore hydrolysed urine. Thermodynamic modelling reveals low or very low equilibrium solute concentrations for cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni) and lead (Pb). Experiments confirmed Cd, Cu and Pb carbonate and hydroxide precipitation upon metal addition in stored urine with a reaction half-life of ca. 7 days. For all metals considered, the maximum specific metal concentrations per gram phosphate or nitrogen showed to be typically several orders of magnitudes lower in urine than in commercially available fertilizers and manure. Heavymetals in struvite precipitated from normal stored urine could not be detected. Phosphate recovery from urine over struvite precipitation is shown to render a product free from most organic micropollutants and containing only a fraction of the already low amounts of heavymetals in urine. PMID:17368503

Towards the development of a potential remediation technology for multiple heavymetals [Zn(II), Cu(II), Cd(II), Cr(VI) and Ni(II)] from contaminated water, present study examined the growth kinetics and heavymetal removal ability of Beauveria bassiana in individual and multi metals. The specific growth rate of B. bassiana varied from 0.025h(-1) to 0.039h(-1) in presence of individual/multi heavymetals. FTIR analysis indicated the involvement of different surface functional groups in biosorption of different metals, while cellular changes in fungus was reflected by various microscopic (SEM, AFM and TEM) analysis. TEM studies proved removal of heavymetals via sorption and accumulation processes, whereas AFM studies revealed increase in cell surface roughness in fungal cells exposed to heavymetals. Present study delivers first report on the mechanism of bioremediation of heavymetals when present individually as well as multi metal mixture by entomopathogenic fungi. PMID:27387415

The feasibility, economics and environmental concerns of producing more domestic oil using thermal enhanced oil recovery (TEOR) are reviewed and the unique nature of geopressured-geothermal (GPGT) fluids for thermal recovery are outlined. Current methods of TEOR are briefly discussed and it is noted that these methods are presently under scrutiny by both federal and state air quality agencies; and moreover, they often involve costly operational and mechanical problems associated with heating water on the surface for injection into the target reservoir. The characteristics of the GPGT resources as seen through previous Department of Energy (DOE) studies from sites in Louisiana and Texas are discussed. These studies indicate sufficient quantities of GPGT fluids can be produced to sustain a TEOR project. The Alworth Field in the south Texas Mirando Trend is proposed as a TEOR pilot site. The target reservoirs for injection of the GPGT fluids are the Jackson and Yegua sandstones of the upper Eocene Epoch. The reservoirs contain an estimated 4 MMbbls of heavy oil in place (OIP) (18.6{degree}API) of which it is estimated that at least 1 MMbbls could be recovered by TEOR. The problems associated with using the GPGT fluids for TEOR include those normally associated with hot water flooding but in addition the reaction of the brine from the geopressured-geothermal reservoir with the target reservoir is uncertain. Under the elevated temperatures associated with GPGT TEOR, actual increased porosity and permeability are possible. 120 refs., 40 figs., 13 tabs.

Three aquatic plants were examined for their ability to remove heavymetals from contaminated water: parrot feather (Myriophylhum aquaticum), creeping primrose (Ludwigina palustris), and water mint (Mentha aquatic). The plants were obtained from a Solar Aquatic System treating municipal wastewater. All the three plants were able to remove Fe, Zn, Cu, and Hg from the contaminated water. The average removal efficiency for the three plant species was 99.8%, 76.7%, 41.62%, and 33.9% of Hg, Fe, Cu, and Zn, respectively. The removal rates of zinc and copper were constant (0.48 mg/l/day for Zn and 0.11 mg/l/day for Cu), whereas those of iron and mercury were dependent on the concentration of these elements in the contaminated water and ranged from 7.00 to 0.41 mg/l/day for Fe and 0.0787 to 0.0002 mg/l/day for Hg. Parrot feather showed greater tolerance to toxicity followed by water mint and creeping primrose. The growth of creeping primrose was significantly affected by heavymetal toxicity. The selectivity of heavymetals for the three plant species was the same (Hg>Fe>Cu>Zn). The mass balance preformed on the system showed that about 60.45-82.61% of the zinc and 38.96-60.75% of the copper were removed by precipitation as zinc phosphate and copper phosphate, respectively. PMID:14680885

Although the use of wetland ecosystems to purify water has gained increased attention only recently, it has been recognized as a wastewater treatment technique for centuries. While considerable research has occurred to quantify the nutrient (nitrogen and phosphorus) removal mechanisms of wetlands, relatively few investigators have focused on the mechanisms of heavymetal removal and uptake by wetland sediments and plants. The quantification of the assimilative capacity of heavymetals by wetland ecosystems is a critical component in the design and use of wetlands for this purpose. A computer model has been developed to simulate the fate and transport of heavymetals introduced to a wetland ecosystem. Modeled water quality variables include phytoplankton biomass and productivity; macrophyte (Nulumbo lutea) biomass; total phosphorus in the water column; dissolved copper in the water column and sediments; particulate copper in the water column and sediments; and suspended solids. These variables directly affect the calculated rate of copper uptake by macrophytes, and the rate of copper recycling as a function of the decomposition of copper-laden biomass litter. The model was calibrated using total phosphorus and chlorophyll a data from the Old Woman Creek Wetland in Ohio. Verification of the model was achieved using data on the copper content of the macrophyte Nelumbo lutea.

In order to remove and recover copper, zinc, cadmium, and chromium from the wastewater treatment sludge generated by an electroplating process, the heavymetal extraction kinetics was studied in a batch reactor using two different extraction agents (nitric and citric acid) at constant agitation speed (150 rpm) and solid to liquid ratio (10 g/L), but varying acid concentrations (0.02-0.10 N), temperatures (25-85 degrees C in nitric acid solution, 25-95 degrees C in citric acid solution), and sludge particle sizes. The shrinking-core model and empirical kinetic model were adopted to analyze the experimental data. Although both models could fit the experimental kinetic data well, the obtained parameters of the shrinking-core model did not show reasonable trends varying with the experimental variables while the empirical model parameters showed significant trends. The experimental and modeling results showed that the metal extraction rates increased with acid concentration, temperature, but decreased with increasing particle size. Nitric acid was found to be more effective than citric acid to extract the heavymetals from the sludge. The extraction activation energies obtained in this study suggested that both a physical diffusion process and a chemical reaction process might play important roles in the overall extraction process. PMID:15993295

The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavymetal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavymetal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavymetal contamination; as a reagent useful in the removal of specific heavymetal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavymetal cation poisoning; as a treatment for the detoxification of specific heavymetal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavymetal cations. 15 figs.

The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavymetal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavymetal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavymetal contamination; as a reagent useful in the removal of specific heavymetal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavymetal cation poisoning; as a treatment for the detoxification of specific heavymetal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavymetal cations.

The abilities of acidophilic chemolithotrophic bacteria and archaea to accelerate the oxidative dissolution of sulfide minerals have been harnessed in the development and application of a biotechnology for extracting metals from sulfidic ores and concentrates. Biomining is currently used primarily to leach copper sulfides and as an oxidative pretreatment for refractory gold ores, though it is also used to recover other base metals, such as cobalt, nickel and zinc. Recent developments have included using acidophiles to process electronic wastes, to extract metals from oxidized ores, and to selectively recovermetals from process waters and waste streams. This review describes the microorganisms and mechanisms involved in commercial biomining operations, how the technology has developed over the past 50 years, and discusses the challenges and opportunities for mineral biotechnologies in the 21st century. PMID:24794631

New high capacity ion-exchange polymer material removes toxic metal cations from contaminated water. Offers several advantages. High sensitivities for such heavymetals as lead, cadmium, and copper and capable of reducing concentrations in aqueous solutions to parts-per-billion range. Removes cations even when calcium present. Material made into variety of forms, such as thin films, coatings, pellets, and fibers. As result, adapted to many applications to purify contaminated water, usually hard wherever found, whether in wastewater-treatment systems, lakes, ponds, industrial plants, or homes. Another important feature that adsorbed metals easily reclaimed by either destructive or nondestructive process. Other tests show ion-exchange polymer made inexpensively; easy to use; strong, flexible, not easily torn; and chemically stable in storage, in aqueous solutions, and in acidic or basic solution.

Abundant and common yeast biomass has been examined for its capacity to sequester heavymetals from dilute aqueous solutions. Live and non-living biomass of Saccharomyces cerevisiae differs in the uptake of uranium, zinc and copper at the optimum pH 4-5. Culture growth conditions can influence the biosorbent metal uptake capacity which normally was: living and non-living brewer's yeast: U > Zn > Cd > Cu; non-living baker's yeast: Zn > (Cd) > U > Cu; living baker's yeast: Zn > Cu approximately (Cd) > U. Non-living brewer's yeast biomass accumulated 0.58 mmol U/g. The best biosorbent of zinc was non-living baker's yeast (approximately 0.56 mmol Zn/g). Dead cells of S. cerevisiae removed approximately 40% more uranium or zinc than the corresponding live cultures. Biosorption of uranium by S. cerevisiae was a rapid process reaching 60% of the final uptake value within the first 15 min of contact. Its deposition differing from that of other heavymetals more associated with the cell wall, uranium was deposited as fine needle-like crystals both on the inside and outside of the S. cerevisiae cells. PMID:7765919

Interest has arisen in heavy-metal contamination of the environment, mostly because of potential hazards to the health of animals and human (directly and/or indirectly). High levels of heavymetals in soil, plants, and the atmosphere are often related to industries, highways, chemical dumping, impure chemical fertilizers, and pesticides containing metals. An important source of heavymetals, especially lead, is from the combustion of leaded gasoline used for transportation. Other heavymetals associated with transportation include nickel, which is also added to gasoline and is contained in engine parts, zinc, and cadmium from tires, lubricating oils, and galvanized parts such as fuel tanks.

A hydrometallurgical process for recovering the total metal values from waste monolithic ceramic capacitors was investigated. The process parameters such as time, temperature, acid concentration, hydrogen peroxide concentration and other reagents (amount of zinc dust and sodium formate) were optimized. Base metals such as Ba, Ti, Sn, Cu and Ni are leached out in two stages using HCl in stage 1 and HCl with H2O2 in stage 2. More than 99% of leaching efficiency for base metals (Cu, Ni, Ba, Ti and Sn) was achieved. Precious metals such as Au and Pd are leached out using aquaregia and nitric acid was used for the leaching of Ag. Base metals (Ba, Ti, Sn, Cu and Ni) are recovered by selective precipitation using H2SO4 and NaOH solution. In case of precious metals, Au and Pd from the leach solution were precipitated out using sodium metabisulphite and sodium formate, respectively. Sodium chloride was used for the precipitation of Ag from leach solution. Overall recovery for base metals and precious metals are 95% and 92%, respectively. Based on the results of the present study, a process flow diagram was proposed for commercial application. PMID:27084106

The understanding of the transport behaviors in porous media resides on the ability to reproduce fundamental phenomena in a lab setting. Experiments with quasi 2D tanks filled with beads are performed to study physical phenomena induced by chemical and fluid dynamic processes. When an alkaline solution containing heavymetals or radionuclides invades a low pH region, mixing due to longitudinal dispersion induces destabilization of the front forming a fast travelling pulse [1]. When the two fluids travel in parallel, instead, mixing induced by transverse dispersion creates a continuous leakage from the alkaline region into the acidic one forming a fast travelling plume [2] (Figure 1). Impact of these phenomena are on aquifers upon leaking of alkaline fluids, rich in heavymetals and radionuclides, from waste storage sites. Here, we report the results from a study where experiments with a quasi 2D tank are performed to analyze the effect of transverse mixing on strontium (Sr2+) transport. To visualize the leaking plume, a fluorescent dye (Fura-2) is added the acidic solution, which has been widely used in biomedical applications [3]. It is the aim of this work to optimize its application under the conditions relevant to this work. Spectrometric measurements of absorption and fluorescence show sensitivity of the dye to the presence of Sr2+ throughout a broad range of pH and Sr2+ concentration (Figure 2). In the absence of Sr2+, no significant absorption and fluorescence was measured, but as Sr2+ was added the relevant peaks increase significantly and sample dilution of tenfold was required to remain within the measuring threshold. These results show a strong sensitivity of the dye to the cation opening the opportunity to use Fura-2 as a tool to visualize heavymetals and radionuclides plumes. References[1] Prigiobbe et al. (2012) GRL 39, L18401. [2] Prigiobbe and Hesse (2015) in preparation. [3] Xu-Friedman and Regehr (2000) J. Neurosci. 20(12) 4414-4422.

The safe disposal of coal combustion residues (CCRs) will remain a major public issue as long as coal is used as a fuel for energy production. Both dry and wet disposal methods of CCRs create serious environmental problems. The dry disposal method creates air pollution initially, and the wet disposal method creates water pollution as a result of the presence of trace and heavymetals. These leached heavymetals from fly ash may become more hazardous when they form toxic compounds such as arsenic sulfite (As2S3) and lead nitrate (N2O6Pb). The available studies on trace and heavymetals present in CCRs cannot ensure environmentally safe utilization. In this work, a novel approach has been offered for the retrieval of trace and heavymetals from CCRs. If the proposed method becomes successful, then the recovered trace and heavymetals may become a resource and environmentally safe use of CCRs may be possible.

The adsorption of aqueous Hg 2+, Pb 2+, Zn 2+ and Cd 2+ complexes on a variety of sulphide minerals has been studied as a function of the solution pH and also as a function of the nature of the ligands in solution. Sulphide minerals are excellent scavengers for these heavymetals. The adsorption is strongly pH dependent, i.e. there is a critical pH at which the adsorption increases dramatically. The pH dependence is related to the hydrolysis of the metal ions. Indirect evidence suggests that the hydrolyzed species are adsorbed directly on the sulphide groups, probably as a monolayer. The results also suggest the presence of MCI n2- n species physisorbed on the adsorbed monolayer. A positive identification of the adsorbed species was not possible using ESCA/XPS.

For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au+ and Cu2+ respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs. PMID:26316021

For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au(+) and Cu(2+) respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs. PMID:26316021

This paper deals with an alternative treatment for recoveringmetals from goethite red mud (RM), which occurs as a by-product at zinc leaching plants. It is derived from the hydrometallurgical treatment of sphalerite, which involves roasting followed by acid attack and subsequent recovery of the zinc by electrodeposition. The leaching mud contains various oxides and hydroxides of iron plus lesser amounts of sulfates of Pb, Zn, Ca, Cd, Ag, In, Se, and other metals. In recent years, numerous attempts have been made to recover the RM or render it inert, particularly by such processes as vitrification or lithification for the production of glass ceramics. The work reported here proposes a treatment involving reduction and magnetic separation to permit the extraction of pure zinc, a high percentage of a pure magnetite, and a harmless slag containing mixed silicates of zinc and lead as well as oxides of minor elements.

Possible mechanisms of the antitoxic action of organoselenium compounds in heavymetal poisoning have been considered. Heavymetal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavymetal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavymetal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavymetal intoxication. PMID:26350735

Heavymetals are naturally occurring elements that have a high atomic weight and a density at least 5 times greater than that of water. Their multiple industrial, domestic, agricultural, medical and technological applications have led to their wide distribution in the environment; raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the U.S. Environmental Protection Agency, and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity. PMID:22945569

Long-term ecological sustainability is incompatible with an open materials cycle. The toxic heavymetals (arsenic, cadmium, chromium, copper, lead, mercury, silver, uranium/plutonium, zinc) exemplify the problem. These metals are being mobilized and dispersed into the environment by industrial activity at a rate far higher than by natural processes. Apart from losses to the environment resulting from mine wastes and primary processing, many of these metals are utilized in products that are inherently dissipative. Examples of such uses include fuels, lubricants, solvents, fire retardants, stabilizers, flocculants, pigments, biocides, and preservatives. To close the materials cycle, it will be necessary to accomplish two things. The first is to ban or otherwise discourage (e.g., by means of high severance taxes on virgin materials) dissipative uses of the above type. The second is to increase the efficiency of recycling of those materials that are not replaceable in principle. Here, also, economic instruments (such as returnable deposits) can be effective in some cases. A systems view of the problem is essential to assess the cost and effectiveness of alternative strategies. PMID:11607259

Heavymetals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity. PMID:22945569

Co-contamination of antibiotics and heavymetals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavymetals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavymetals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavymetals required to induce antibiotic resistance, i.e., the minimum heavymetal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavymetal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavymetal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavymetal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments. PMID:26426011

Co-contamination of antibiotics and heavymetals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavymetals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavymetals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavymetals required to induce antibiotic resistance, i.e., the minimum heavymetal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavymetal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavymetal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavymetal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments. PMID:26426011

This article describes the potential for use of composts from green waste and from municipal solid wastes for agricultural use in Italy. The accumulation of heavymetals in compost-amended soils and crops was evaluated and the influence of these composts on plant productivity was studied. Green compost was obtained from vegetable organic residues; municipal solid waste derived compost was obtained from the aerobic biostabilization of a mixture of the organic biodegradable fraction of municipal solid waste and sewage sludge. The two composts had good chemical characteristics and their use caused no pollution to soil and plants. The overall fertilizing effect was higher for green compost even though green compost and municipal solid waste derived compost had similar contents of primary elements of fertility.

Heavymetal fluoride glasses (HMFG) are potentially useful as optical components in a wide range of devices. Their utilization has so far been delayed mainly because of insufficient material purity and inadequate processing conditions. However, as the result of numerous research efforts, these problems are gradually diminishing, and it now seems likely that the ultimate limitations for use of HMFG components, at least in those applications in which high optical transparency is not a prerequisite, will be imposed by more intrinsic instabilities of the glasses themselves. These include their strong tendency to crystallize on quenching and subsequent reheating, low mechanical and chemical durability, and the possibility that they will undergo significant physical aging in situ. Experimental data relating to these problems have now been obtained, and their relative importance is assessed in this paper.

It is estimated that the Departments of Defense, Energy, and Agriculture will spend up to 300 billion federal dollars on environmental remediation during the next century. Current remediation processes can be expensive, non-aesthetic, and non-versatile. Therefore, the need exists for more innovative and cost effective solutions. Phytoremediation, the use of vegetation for the remediation of contaminated sediments, soils, and ground water, is an emerging technology for treating several categories of persistent, toxic contaminants. Although effective, phytoremediation is still in a developmental stage, and therefore is not a widely accepted technology by regulatory agencies and public groups. Research is currently being conducted to validate the processes effectiveness as well as increase regulatory and community acceptance. This research will focus on the ability of plants to treat an aquifer contaminated with heavymetals and radionuclides. Specifically, the effectiveness of hydroponically grown dwarf sunflowers and mustard seed will be investigated.

1. In the Federal Republic of Germany two staple foodstuffs, cereals and milk, are regularly checked by means of monitoring programmes for their content of heavymetals, this check being representative for the whole country. Other foodstuffs are analysed in the laboratories of the Food Control Authorities, but these inspections are carried out rather sporadically and are not yet of a "monitoring" nature. 2. The measured values from a number of laboratories are fed into a central data bank (Datenbank-ZEBS) at the Federal Health Office and are thus available for statistical and hygienic evaluation. 3. At present, information is available on the lead, cadmium and mercury content of foodstuffs which represent roughly 70 to 80 per cent of the food consumed by an average adult. The intake of lead, cadmium and mercury due to the consumption of these foodstuffs has been calculated and extrapolated to the complete food consumption. It was found that the value ascertained are clearly lower than the toxicological threshold values published by FAO/WHO. 4. Nevertheless, the intake needs to be limited, because the average heavymetal content of some foodstuffs has increased, probably because of anthropogenic reasons. This is especially likely to apply to the cadmium content of wheat. To attempt a restriction by regulation, is at present not considered in Germany to be the optimal solution. Instead, the Federal Health Office has published guidance values which contain an appeal to the foodstuff industry and food control authorities to investigate the causes, whenever these guidance values are approached or exceeded, with the objective of avoiding high levels. PMID:7456855

Emissions from major highways contain different kinds of contaminants such as heavymetals, polycyclic aromatic hydrocarbons and road salts which can occur in both particulate and dissolved form. Pollutants are transferred to the environment via aerial transport or the infiltration of road runoff and spray water. A significant rate of the road runoff infiltrates into the Embankment which is usually built during road construction and located next to the road edge. Especially in the long term development there is an increasing problem of soil contamination and groundwater pollution. According to valid German law, newly constructed hard shoulders have to provide a specific bear-ing capacity to enable trafficability in emergency cases. Therefore the applicable materials consist of accurately defined gravel-soil mixtures, which can fulfil this requirement. To determine and com-pare the total and dissolved concentrations of Pb, Cd, Zn, Cu, Ni, Cr in the road runoff and seep-age water of newly constructed embankments, we installed 6 Lysimeter along the edge of the German highway A115. Three lysimeter were filled with different materials which are recently used for embankment construction in Germany. Three further lysimeter where installed and filled with plain gravel, to observe the distribution, quantity and quality of road runoff. Fist results showed that heavymetal concentrations determined in the road runoff were compara-ble to literature values. The solute concentrations in the seepage water of the different embank-ment materials do not show considerable differences and exceed the trigger values of the German Federal Soil Protection & Contamination Ordinance (BBodSchV) only sporadically. Total concentra-tions of the seepage water are significantly higher than solute concentrations and clearly differ be-tween stable and non stable variant. In order to estimate the risk of groundwater pollution further monitoring of seepage water quality is necessary.

Investigates the relationship between preference for heavymetal music and vulnerability to suicide among high school students. Results indicate that preference for heavymetal music among adolescents may be sign of increased suicidal vulnerability, but also suggests that the source of the problem may lie more in personal and familial…

Fifty-four male and 30 female adolescents who like heavymetal music were compared on various outcome variables to 56 male and 105 female peers who do not like it. Those who like heavymetal report a wider range of reckless behavior than those who do not like it. (SLD)

A major emphasis has been placed on the bioremediation of organic compounds and their fate and transport throughout the environment. However, another important class of chemicals polluting our environment are inorganic, particularly heavymetals and metalloids. Heavymetals are elements of the Per...

In order to investigate stabilization of heavymetals in ceramsite made with sewage sludge as an additive, the configuration of heavymetals in ceramsite was analysed by XRD and while leaching tests were conducted to find out the effect of sintering temperature (850 degrees C, 900 degrees C, 950 degrees C, 1000 degrees C, 1100 degrees C, and 1200 degrees C), pH (1, 3, 5, 7, 9, and 12), and H2O2 concentration (0.5molL(-1), 1molL(-1), 1.5molL(-1), 3molL(-1), and 5molL(-1)) on stabilization of heavymetals (Cd, Cr, Cu, and Pb) in ceramsite. The results indicate that leaching contents of heavymetals do not change above 1000 degrees C and sintering temperature has a significant effect on stabilization of heavymetals in ceramsite; leaching contents of heavymetals decrease as pH increases and increase as H2O2 concentration increases. XRD analysis reveals that the heavymetals exist in steady forms, mainly Pb2O(CrO(4)), CdSiO3, and CuO at 1100 degrees C. It is therefore concluded that heavymetals are properly stabilized in ceramsite and cannot be easily released into the environment again to cause secondary pollution. PMID:17692459

Heavymetals from sewage sludge have been reported to concentrate in producers, in primary consumers, and in detritivores. Little research, however, has focused on the uptake of heavymetals from sewage sludge by secondary consumers. The Family Soricidae represents an ideal mammalian taxonomic group to investigate rates of heavymetal transfer between primary and secondary consumers. The least shrew (Cryptotis parva) was used to evaluate the accumulation of heavymetals while maintained on a diet of earthworms collected from long-term sludge-treated old-field communities. This secondary consumer is distributed widely through the eastern United States and its natural diet includes earthworms which makes it a potentially good indicator of heavymetal transfer in areas treated with municipal sludge.

The Ria of Huelva estuary, in SW Spain, is known to be one of the most heavymetal contaminated estuaries in the world. River contribution to the estuary of dissolved Cu, Zn, Mn, Cr, Ni, Cd, and As were analysed for the period 1988-2001. The obtained mean values show that this contribution, both because of the magnitude of total metals (895.1 kg/h), composition, toxicity (8.7 kg/h of As+Cd+Pb) and persistence, is an incomparable case in heavymetal contamination of estuaries. The amount and typology of heavymetal discharge to the Ria of Huelva are related to freshwater flow (and, consequently, to rainfall); as a result, two different types of heavymetal discharge can be distinguished in the estuary: during low water (50% of the days), with only 19.3 kg/h of heavymetals, and during high water or flood (17% of the days), where daily maximum discharge of 72,475 kg of heavymetals were recorded, from which 1481 kg were of As, 470 kg of Pb, and 170 kg of Cd. In the most frequent situation (77% of the days), the Odiel River discharges from 90% to 100% of the freshwater received by the estuary. Despite this, the high concentration of heavymetals in the Tinto River water causes this river to discharge into the Ria of Huelva 12.5% of fluvial total dissolved metal load received by the estuary. PMID:15031016

The objective of this study was to evaluate the characteristics of mangium bark and its biosorbent ability to reduce heavymetal ions in standard solutions and wastewater and to assess changes in bark characteristics after heavymetal absorption. The experiments were conducted to determine heavymetal absorption from solutions of heavymetals alone and in mixtures as well as from wastewater. The results show that mangium bark can absorb heavymetals. Absorption percentages and capacities from single heavymetal solutions showed that Cu(2+) > Ni(2+) > Pb(2+) > Hg(2+), while those from mixture solutions showed that Hg(2+) > Cu(2+) > Pb(2+) > Ni(2+). Wastewater from gold mining only contained Cu, with an absorption percentage and capacity of 42.87 % and 0.75 mg/g, respectively. The highest absorption percentage and capacity of 92.77 % and 5.18 mg/g, respectively, were found for Hg(2+) in a mixture solution and Cu(2+) in single-metal solution. The Cu(2+) absorption process in a single-metal solution changed the biosorbent characteristics of the mangium bark, yielding a decreased crystalline fraction; changed transmittance on hydroxyl, carboxyl, and carbonyl groups; and increased the presence of Cu. In conclusion, mangium bark biosorbent can reduce hazardous heavymetal ions in both standard solutions and wastewater. PMID:27179811

The aim of our investigation was to determine of HM content in the hair of people and animals. Two of the main essential elements-Zn and Cu and two of the supertoxical heavymetals- Pb and Cd were chosen. The investigations were conducted in Russian Federation and Belarus Republic in 2001-2002. About 500 hair samples of people, dogs, cats, cattle, horses, yaks, pigs, sheep goats and rabbits were studied by the stripping voltammetric analysis (SVA) method with TA- 2 analyzer to determine Zn, Cu, Pb and Cd concentrations. The hair samples were prepared according to the methods developed in Tomsk University (Russia) and improved by the authors. The essence of the methods is the multiconsecutive burning of hair samples to ashes and boiling them in concentrated acids to dissolve chemical combinations and transform their metals into ion forms. The zinc concentration was the highest in all hair samples (58.65 ... 195.15 mg/kg). The copper content was several times less (5.49 ... 22.63 mg/kg). Lead and cadmium were detected in relatively low amounts (0.32 ... 2.42 mg/kg and 0.04 ... 0.92 mg/kg respectively). The highest Pb and Cd levels were detected in cats and people hair.

The crayfish, Onconectes virifis, is a bottom dweller and eats insect larvae, worms, crustaceans, small snails, fishes, and dead animal matter. They can be used to monitor the aquatic environment such as lakes, ponds and creeks. To monitor the environmental contamination of heavymetals (Hg, Pb, Cd, Cu, Co, Ni, and Zn) in Tuskegee Lake, Tuskegee, Alabama, adult crayfish were collected and analyzed for these metals. The Pb, Cd, Cu, Ni, and Zn concentrations were 3.91, 0.22, 8.06, 1.11, and 33.37 ppm in muscle and 28.98, 1.15, 9.86, 2.1 8, and 32.62 ppm in exoskeleton of crayfish, respectively. The concentrations of Pb and Cd were significantly higher in exoskeleton than those of muscle. However, the concentrations of Cu, Ni, and Zn did not show any significant difference between the muscle and the exoskeleton of the crayfish. The concentrations of Hg and Co were undetected in both the exoskeleton and muscle of the crayfish.

Seasonal variation of heavymetal contents in leaves and their relationships with soil heavymetal pollution levels were studied through measuring and analyzing the leaves of the common tree species in Beijing and soil heavymetal contents, to detect heavymetal accumulation ability of plant leaves. The results showed that: (1) the contents of Cu, Pb, Zn in plant leaves first decreased and then increased, again declined with changing the seasons (from spring to winter). Cr concentration showed the trend of first increase and then decrease from spring to winter, and the highest in the autumn; the accumulation capacities of Cu for Babylonica and Japonica were higher in the spring, summer and autumn, while Tabuliformis was in winter; the higher accumulation capacities for Cr, Pb were Japonica and Platycladus, and in winter were Platycladus and Bungeana; the higher accumulation capacities for Zn were Babylonica and Bungeana, while Platycladus in winter; (2) the pollution degree of four kinds of heavymetals (Cu, Cr, Pb, Zn) from downtown to suburbs showed that: Jingshan (C =2.48, C is contamination factor) > Olympic (C = 1.27) > Songshan (C = 1.20) > Shuiguan (C = 1. 18); (3) the heavymetals concentration of same plant leaves in the water of the Great Wall changed larger, but those in the other three areas showed that: Jingshan > Olympic > Songshan; the ability of same species leaf to absorb different sorts of heavymetals showed that: Zn >Cu >Pb >Cr; the difference between Zn content and Cr content was significant (P <0.01); (4) the relationship between heavymetal content in plant leaves and soil heavymetal pollution levels presented a quadratic polynomial relation; the significant correlation was found between other three heavymetal contents of plant samples and soil samples, but they were not the case for the Cu, and the correlation coefficients were above 0. 9. PMID:25055683

The project examined fate and effects of heavymetals on biological communities in the upper Arkansas River Basin. The principal objectives of the research were: (1) to measure the impact of heavymetals (Cd, Cu, and Zn) on benthic invertebrate communities in the Arkansas River; (2) to delineate zones of high impact, moderate impact, and recovery based on the distribution and abundance of these organisms; (3) to examine seasonal variation in effects of metals on benthic communities; (4) to examine the potential transfer of heavymetals from benthic invertebrates to brown trout, Salmo trutta.

Bismuth film electrodes (BiFEs) have a potential to replace toxic mercury used most frequently for determination of heavymetals (Cd, Pb, Zn) by anodic stripping voltammetry. We prepared a graphite disc electrode (0.5 mm in diameter) from a pencil-lead rod and developed a nitrogen doped diamond-like carbon (NDLC) microelectrode array consisting of 50 625 microdiscs with 3 μm in diameter and interelectrode distances of 20 μm on a highly conductive silicon substrate as a support for BiFEs. The disc graphite BiFE was used for simultaneous determination of Pb(II), Cd(II) and Zn(II) by square wave voltammetry (SWV) in an aqueous solution. We found the optimum bismuth-to-metal concentration ratio in the solution to be 20. The dependence of the stripping responses on the concentration of target metals was linear in the range from 1×10 -8 to 1.2×10 -7 mol/L. Detection limits 2.4×10 -9 mol/L for Pb(II), 2.9×10 -9 mol/L for Cd(II) and 1.2×10 -8 mol/L for Zn(II) were estimated. A bismuth-plated NDLC microelectrode array was used for Pb(II) determination by differential pulse voltammetry (DPV) in an aqueous solution. We found that the stripping current for bismuth-plated NDLC array was linear in the concentration range of Pb(II) from 2×10 -8 to 1.2×10 -7 mol/L. The detection limit 2.2×10 -8 mol/L was estimated from a calibration plot.

Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavymetal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavymetals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavymetals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavymetals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavymetals induced oxidative stress and their toxicity management in mammals. PMID:25184144

Heavymetal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavymetal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavymetal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavymetals are reviewed in this article. The problems and future perspectives of this technology are discussed. PMID:23915280

Urban rivers are often utilized by the local residents as water source, but they can be polluted by heavymetals due to industrialization. Here, the concentrations, toxicity, speciation and vertical profiles of heavymetals in sediment were examined to evaluate their impact, dispersal and temporal variation in Dongbao River. Results showed that the sediment in the industrialized areas was seriously contaminated with Cr, Cu and Ni which posed acute toxicity. Heavymetals, except Cr and Pb, were mainly associated with non-residual fractions, indicating their high mobility and bioavailability. The non-industrialized areas were also seriously contaminated, suggesting the dispersal of heavymetals along the river. The surface sediment could be more contaminated than the deep sediment, indicating the recent pollution events. Overall, when the point sources are not properly regulated, intense industrialization can cause both serious contamination and dispersal of heavymetals, which have far-reaching consequences in public health and environment. PMID:26856647

Environmental safety has been the focus worldwide, where involved are the pollutions of heavymetals, pesticides and persistent organic pollutants. Fertilizer has become one of the polluting sources of heavymetals, which are very deleterious to human health and environmental safety. Heavymetals are difficult to metabolize in human body and very harmful, so research on the pollution of heavymetals is considered increasingly important. The pollution sources of heavymetals include waste residue, waste water and exhaust gas from industry and automobile, and garbage from human life. The heavymetals in fertilizer can endanger the human body by the crop containing heavymetals. Two kinds of nitrogen fertilizer were analyzed in terms of the content of heavymetals by ICP-MS, and the results showed that the content of 10 kinds of heavymetals (Al, Ti, Cr, Ni, Cu, Zn, As, Cd, Hg and Pb) in (NH4)2SO4 was 1345.13, 35.12, 2539.27, 287.26, 674.05, 270.79, 42.54, 22.13, 27.20 and 123.87 ng x g(-1) respectively; and in CO(NH2)2 it is 71.59, 5.36, 1167.71, 188.60, 7.46, 64.45, 10.55, 0.00, 0.09 and 3.71 ng x g(-1) respectively. All the data showed that CO(NH2)2 contained much less heavymetals than (NH4)2SO4, so we should select CO(NH2)2 as the nitrogen fertilizer in agricultural production. PMID:19123422

Heavymetals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavymetals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavymetals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavymetals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavymetals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavymetals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavymetals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavymetals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavymetals for maximum uptake during chelate-assisted phytoremediation.

Organic spintronics is a new emerging field that promises to offer the full potential of chemistry to spintronics, as for example high versatility through chemical engineering and simple low cost processing. However, one key challenge that remains to be unlocked for further applications is the high incompatibility between spintronics key materials such as high Curie temperature Co, Ni, Fe (and their alloys) and wet chemistry. Indeed, the transition metal proneness to oxidation has so far hampered the integration of wet chemistry processes into the development of room temperature organic spintronics devices. As a result, they had mainly to rely on high vacuum physical processes, restraining the choice of available organic materials to a small set of sublimable molecules. In this letter, focusing on cobalt as an example, we show a wet chemistry method to easily and selectively recover a metallic surface from an air exposed oxidized surface for further integration into spintronics devices. The oxide etching process, using a glycolic acid based solution, proceeds without increasing the surface roughness and allows the retrieval of an oxygen-free chemically active cobalt layer. This unlocks the full potential of wet chemistry processes towards room temperature molecular spintronics with transition metals electrodes. We demonstrate this by the grafting of alkylthiols self-assembled monolayers on recovered oxidized cobalt surfaces.

Plants are under the continual threat of changing climatic conditions that are associated with various types of abiotic stresses. In particular, heavymetal contamination is a major environmental concern that restricts plant growth. Plants absorb heavymetals along with essential elements from the soil and have evolved different strategies to cope with the accumulation of heavymetals. The use of proteomic techniques is an effective approach to investigate and identify the biological mechanisms and pathways affected by heavymetals and metal-containing nanoparticles. The present review focuses on recent advances and summarizes the results from proteomic studies aimed at understanding the response mechanisms of plants under heavymetal and metal-containing nanoparticle stress. Transport of heavymetal ions is regulated through the cell wall and plasma membrane and then sequestered in the vacuole. In addition, the role of different metal chelators involved in the detoxification and sequestration of heavymetals is critically reviewed, and changes in protein profiles of plants exposed to metal-containing nanoparticles are discussed in detail. Finally, strategies for gaining new insights into plant tolerance mechanisms to heavymetal and metal-containing nanoparticle stress are presented. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock. PMID:26940747

The major threats to human health from heavymetals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavymetals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavymetal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavymetals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavymetals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavymetals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

In this review, we evaluate the reports published between 1993 and 2011 that address the heavymetal accumulation in 88 medicinal plant species. We compare the safe limits for heavymetals set by governmental agencies vs. the levels at which such metals actually exist in selected medicinal plants. We also evaluate the uses and effectiveness of medicinal plants in health care, and assess the hazards of medicinal plant uses, in view of the growing worldwide use of medicinal plants. From our extensive review of the literature, we discovered that a maximum permissible level (MPL) of Pb is exceeded in 21 plant medicine species, Cd in 44 species, and Hg in 10 species. Vetiveria zizanioides a potential candidate species for the treatment of cardiovascular diseases absorb a wide range of heavymetals from metal-contaminated soils. We believe that this species is the single most impressive example of a potentially hazardous medicinal plant. Based on our review, we endorse the hypothesis that heavymetal accumulation by medicinal plants is mainly caused by extraction of soluble metals from contaminated soil, sediments and air. One continuing problem in protecting consumers of plant-based medicines is that permissible levels of all heavymetals in herbal medicine have not yet been standardized by regulating governmental entities. Moreover, there are few limit tests that exist for heavymetal content of medicinal plants, or permissible limits for essential dietary minerals, in most medicinal plants. The dearth of such limits hamstrings development of medicinal plant research and delays the release of either new or improved versions of medicinal plants or their components. In the present review, we emphasize that medicinal plants are often subjected to heavymetal contamination and that the levels at which these heavymetals sometimes occur exceeds permissible levels for some species. Therefore, collecting medicinal plants from areas that are, or may be, contaminated should be

Retention reactions in soils are important processes that govern the fate of chemical contaminants such as heavymetals in groundwaters. The ability to predict the mobility of heavymetals in the soil and the potential contamination of groundwater supplies is a prerequisite in any program aimed at protecting groundwater quality. Mathematical models that describe the potential mobility of heavymetals must include description of the retention processes in the soil matrix. Extensive research has been carried out to describe the retention-release behavior of several heavymetals in soils. Fuller, Alesii et al., Dowdy and Volk, Ellis et al., and Kabata-Pendias and Pendias, among others, have presented overviews of retention-release and leaching investigations for several heavymetals in soils. The publications also describe soil physical and chemical properties that influence the fate of heavymetals in the soil environment and their potential leaching to groundwater supplies. Over the last two decades, however, only a limited number of investigations have attempted to quantify the heavymetals in laboratory soil columns or in soil profiles under field conditions have only recently appeared in the literature.

Many areas have been heavily contaminated by heavymetals from industry and are not suitable for food production. The consumption of contaminated foods represents a health risk in humans, although some heavymetals are essential at low concentrations. Increasing the concentrations of essential elements in foods is one goal to improve nutrition. The aim of this study was to increase the accumulation of heavymetals in plant foods by the external application of putrescine. The levels of cadmium, zinc and iron were measured in different vegetables grown in hydroponic medium supplemented with heavymetals and compared with those grown in a reference medium. The estimated daily intake, based on the average daily consumption for various vegetable types, and the influence of polyamines on metal uptake were calculated. PMID:27451175

We have investigated adsorption of Cd(II) and Pb(II) at pH 2-6.7 onto the biomaterials chitosan, coffee, green tea, tea, yuzu, aloe, and Japanese coarse tea, and onto the inorganic adsorbents, activated carbon and zeolite. High adsorptive capabilities were observed for all of the biomaterials at pH 4 and 6.7. In the adsorption of Cd(II), blend coffee, tea, green tea, and coarse tea have comparable loading capacities to activated carbon and zeolite. Although activated carbon, zeolite, and chitosan are utilized in a variety of fields such as wastewater treatment, chemical and metallurgical engineering, and analytical chemistry, these adsorbents are costly. On the other hand, processing of the test biomaterials was inexpensive, and all the biomaterials except for chitosan were able to adsorb large amounts of Pb(II) and Cd(II) ions after a convenient pretreatment of washing with water followed by drying. The high adsorption capability of the biomaterials prepared from plant materials is promising in the development of a novel, low-cost adsorbent. From these results, it is concluded that heavymetal removal using biomaterials would be an effective method for the economic treatment of wastewater. The proposed adsorption method was applied to the determination of amounts of Cd(II) and Pb(II) in water samples. PMID:15373400

It is well known that heavymetals (HM) are extremely dangerous pollutants influencing to metabolism in animals' organisms. The vitamin C is one of the most important metabolites taking part in many biochemical processes. We studied the influence of main essential HM-Zn and Cu as well as the based supertoxical elements - Cd and Pd on ascorbic acid level in serum. The studies were carried out in Tulinskoe farm of Novosibirsk region. The objects of investigations were piglets (2 month after weaning) and 6-month pigs of Early Ripe Meat breed. The levels of HM in bristle were found by stripping voltammetric analysis using the TA-2 analyzer. Vitamin C content was determined by I.P. Kondrakhin (1985) method using 2,2-dipyridyl. The significant negative correlations between Pb, Cd content and vitamin C (-0.46 ± 0.18, -0.47 ± 0.19) in 6-month pigs were determined. The tendencies of negative correlation between all HM levels in hair and ascorbic acid level in plasma of piglets were revealed. Thus, the obtained correlations let us to suppose that all studied HM influence on 1-gulono-gamma-lactone oxidase and other vitamin C metabolism enzymes activity.

Heavymetals are required by all organisms for normal function, but high levels of heavymetals are toxic. Therefore, homeostasis of these metals is crucial. In the human malaria-causing agent Plasmodium falciparum, the mechanisms of heavymetal transport have yet to be characterized. We have developed a P. falciparum line resistant to heavymetals from a wild-type line sensitive to heavymetals. A molecular and biochemical analysis of the involvement of the P. falciparum multidrug resistance 2 (pfmdr2) gene, an ABC-type transporter, in heavymetal homeostasis was studied. Using a novel uptake assay applied on these two strains, it was demonstrated that, when exposed to heavymetals, the sensitive line accumulates metal, whereas no accumulation was observed in the resistant line. The accumulation occurs within the parasite itself and not in the cytoplasm of the red blood cell. This difference in the accumulation pattern is not a result of amplification of the pfmdr2 gene or of a change in the expression pattern of the gene in the two lines. Sequencing of the gene from both lines revealed a major difference; a stop codon is found in the sensitive line upstream of the normal termination, resulting in a truncated protein that lacks 188 amino acids that contain a portion of the essential cytoplasmatic transporter domain, thereby rendering it inactive. In contrast, the resistant line harbors a full-length, active protein. These findings strongly suggest that the PFMDR2 protein acts as an efflux pump of heavymetals. PMID:16849328

Anthropogenic inputs of pollutants such as heavymetals into the marine environment have increased their levels to large extents within past a few decades. These pollutants tend to accumulate in the bottom sediments. As a result, ecosystems such as seaports or other industrialized coastal areas that have chronic inputs of metals have highly contaminated sediments. This characteristic has led to concerns over the ecological effects that may be associated with sediment quality. Of particular concern are toxic effects and the potential for bioaccumulation of metals in biota exposed to the sediments. The availability of heavymetals to the biomass of a polluted region is the prime concern both in terms of the prediction of the effects of metal pollution on an ecosystem and in terms of possible human health risks. With growing interest on environmental issues, several intriguing questions related to heavymetals are often raised. This review addresses the basic concepts, sources, speciation, mode of action, levels, analytical measurement, bioavailability, bioaccumulation, biological role and toxicity of heavymetals in the marine environment. Lead, Cadmium, Zinc, Copper, Manganese, Iron, Mercury, Arsenic and Barium are selected because these metals are common and are often at measurable levels in marine samples. An attempt has been made to answer the queries presented by the environmentalists working on various aspects of heavymetal pollution in the marine environment

The popularity of goat farming is increasing in the southeastern region of the United States. Baseline values of Hg, Pb, and Cd are not available in goat tissues in the United States. These values are needed when monitoring food for heavymetal contamination which may be associated with urbanization and industrialization. Due to human activities or anthropogenic sources of metals in the environment, high concentrations of these metals have been observed in herbage and animal tissues. It has also been reported that toxic heavymetals are concentrated mostly in kidneys and livers of animals. The risk of exposure of humans to heavymetals contained in edible organs of animals has received widespread concern. The objectives of this study were to (i) measure the levels of Hg,Pb, and Cd in livers and kidneys of goats; and (ii) determine whether accumulation of these metals is related to age and/or sex. 20 refs., 3 tabs.

From poisoning caused by lead-based paint on domestic buildings to groundwater contamination by naturally occurring arsenic deposits in India, heavy-metal toxicity is a global health problem. Contaminated ground water and acute cases of heavy-metal poisoning are treated with chelators to remove the heavymetals from the contaminated site or person. This review discusses the effort to generate heavy-metal chelators through peptide de novo design. De novo design entails the design of a primary sequence that will precisely fold into a predetermined secondary and tertiary protein structure. The first-generation peptide chelator used to initiate this investigation is the three-stranded coild coil containing Cys. Cys provides a potential trigonal binding site with soft thiolate ligands, which has been proposed to provide specific interactions with heavymetals. This hypothesis derives from the observation that similar sites on natural proteins show selectivity for heavymetals over other essential metals, such as Zn or Mg. A description of two systems, the TRI series and the IZ-AC peptide, is given, highlighting the interaction of these peptides with Hg, Cd, As and Pb. Arguments are also presented for the potential use of three-helix bundles as a second-generation design. PMID:12478724

Heavymetals and their derivatives can cause various diseases. Numerous studies have evaluated the possible link between exposure to heavymetals and various cancers. Recent data show a correlation between heavymetals and aberration of genetic and epigenetic patterns. From a literature search we noticed few experimental and epidemiological studies that evaluate a possible correlation between heavymetals and brain tumors. Gliomas arise due to genetic and epigenetic alterations of glial cells. Changes in gene expression result in the alteration of the cellular division process. Epigenetic alterations in brain tumors include the hypermethylation of CpG group, hypomethylation of specific genes, aberrant activation of genes, and changes in the position of various histones. Heavymetals are capable of generating reactive oxygen assumes that key functions in various pathological mechanisms. Alteration of homeostasis of metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and alteration of proteins. In this study we summarize the possible correlation between heavymetals, epigenetic alterations and brain tumors. We report, moreover, the review of relevant literature. PMID:25646073

Heavymetals and their derivatives can cause various diseases. Numerous studies have evaluated the possible link between exposure to heavymetals and various cancers. Recent data show a correlation between heavymetals and aberration of genetic and epigenetic patterns. From a literature search we noticed few experimental and epidemiological studies that evaluate a possible correlation between heavymetals and brain tumors. Gliomas arise due to genetic and epigenetic alterations of glial cells. Changes in gene expression result in the alteration of the cellular division process. Epigenetic alterations in brain tumors include the hypermethylation of CpG group, hypomethylation of specific genes, aberrant activation of genes, and changes in the position of various histones. Heavymetals are capable of generating reactive oxygen assumes that key functions in various pathological mechanisms. Alteration of homeostasis of metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and alteration of proteins. In this study we summarize the possible correlation between heavymetals, epigenetic alterations and brain tumors. We report, moreover, the review of relevant literature. PMID:25646073

Municipal wastewater may contain heavymetals, which are hazardous to the environment and humans. With stringent regulations concerning water reuse and sludge utilization in agriculture, there is a great need to determine levels of heavymetals in liquid wastes, sludges and agricultural crops. The state of Kuwait has programs to utilize waste sludge produced at wastewater treatment plants as soil conditioner and fertilizer for greenery and agricultural development projects and to reuse treated wastewater effluents in irrigation. The common metals found in Kuwait's raw wastewater and sludge are Cd, Cr, Cu, Hg, Ni, Pb, and Zn. The effects of accumulation of heavymetals in soil are long lasting and even permanent. In this study, the variations in the concentration levels of heavymetals were measured in wastewater and sludge produced at Ardiya municipal wastewater treatment plant in Kuwait. A relationship was observed between the concentrations of heavymetals in treated wastewater and sludge used for agriculture and the level of accumulated heavymetals found in residual tissues of some crops. PMID:15027823

Medicinal plants may carry residuals of environmentally persistent pesticides or assimilate heavymetals in varying degrees. Several factors may influence contaminant accumulation, including species, level and duration of contaminant exposure, and topography. As part of a progra...

Heavymetal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavymetals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavymetals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavymetals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed. PMID:27131999

In recent years, heavymetal uptake by biopolymer gels, such as Cal-Alginate or chitosan, has been studied by various methods. This is of interest because such materials might be an alternative to synthetical ion-exchange resins in the treatment of industrial waste waters. Most of the work done in this field consisted of studies of equilibrium absorption of different heavymetal ions with dependence on various experimental parameters. In some publications, the kinetics of absorption were studied, too. However, no experiments on the spatial distribution of heavymetals during the absorption process are known to us. Using Cu as an example, it is demonstrated in this article that NMR microscopy is an appropriate tool for such studies. By the method presented here, it is possible to monitor the spatial distribution of heavymetal ions with a time resolution of about 5 min and a spatial resolution of 100 {mu}m or even better. 14 refs., 10 figs.

The purpose of this paper is to present an overview of the mechanisms and application of a peat/wetland treatment system for heavymetal removal from wastewater. The mechanisms involved in the removal of heavymetals are complex and difficult to predict, however, peat has been proven to be an effective medium to remove metals. The successful design of a peat/wetland treatment system for acid mine drainage is presented to emphasize the low cost and minimal maintenance involved in this passive metal removal technique.

The aim of this study was to investigate the variation in plant communities growing on metal-enriched sites created by historical Zn–Pb mining. The study sites were 65 small heaps of waste rock covered by grassland vegetation and scattered mostly over agricultural land of southern Poland. The sites were described in terms of plant coverage, species richness and composition, and the composition of plant traits. They were classified using phytosociological methods and detrended correspondence analysis. Identified plant communities were compared for vegetation parameters and habitat properties (soil characteristics, distance from the forest) by analysis of variance. The variation in plant community parameters was explained by multiple regression, in which the predictors were properties of the habitat selected on the basis of factor analysis. Grasslands that developed at low and high concentrations of heavymetals in soil were similar to some extent: they were composed on average of 17–20 species (per 4 m(2)), and their total coverage exceeded 90%. The species composition changed substantially with increasing contamination with heavymetals; metal-sensitive species withdrew, while the metal-tolerant became more abundant. Other important predictors of community structure were: proximity to the forest (responsible for the encroachment of competitive forest species and ruderals), and the thickness of the surface soil (shallow soil favored the formation of the heavymetal grassland). The heavymetal grassland was closely related to the dry calcareous grasslands. The former was an earlier succession stage of the latter at low contamination with heavymetals. PMID:26493699

In this work the resistance of 172 motile Aeromonas isolates recovered from raw drinking water supplies (56), irrigation waters (60) and runoff waters receiving sewage (56), to some antibiotics and heavymetals was investigated by agar diffusion and agar dilution methods. A high proportion of isolates from all water sources showed resistance to carbenicillin, erythromycin, streptomycin, cephradine and cadmium, and susceptibility to chloramphenicol, kanamycin, gentamicin, tetracycline, nalidixic acid, trimethoprim-sulphametoxazole and chromium. No amikacin-resistant Aeromonas were recovered. No relationship was found between antimicrobial resistance and Aeromonas species, with the exception of cephradine, that exhibited a significantly higher activity against the A. sobria isolates than the other Aeromonas species (P < 0.05). Moderately polluted waters showed lower antibiotic multiresistance and metal susceptibility than unpolluted and highly polluted ones. Although significant differences (P < 0.05), between resistance frequencies to erythromycin, carbenicillin, streptomycin and cephradine were found among isolates from different sources, the antimicrobial resistance patterns of aeromonads could not be related to the level of faecal pollution. These results indicate that aeromonads resistant to antibiotics and heavymetals are easily recovered from water sources in Chile, posing a potential public health risk. PMID:9926432

Toxic chemical pollutants such as heavymetals (HMs) are commonly present in urban stormwater. These pollutants can pose a significant risk to human health and hence a significant barrier for urban stormwater reuse. The primary aim of this study was to develop an approach for quantitatively assessing the risk to human health due to the presence of HMs in stormwater. This approach will lead to informed decision making in relation to risk management of urban stormwater reuse, enabling efficient implementation of appropriate treatment strategies. In this study, risks to human health from heavymetals were assessed as hazard index (HI) and quantified as a function of traffic and land use related parameters. Traffic and land use are the primary factors influencing heavymetal loads in the urban environment. The risks posed by heavymetals associated with total solids and fine solids (<150μm) were considered to represent the maximum and minimum risk levels, respectively. The study outcomes confirmed that Cr, Mn and Pb pose the highest risks, although these elements are generally present in low concentrations. The study also found that even though the presence of a single heavymetal does not pose a significant risk, the presence of multiple heavymetals could be detrimental to human health. These findings suggest that stormwater guidelines should consider the combined risk from multiple heavymetals rather than the threshold concentration of an individual species. Furthermore, it was found that risk to human health from heavymetals in stormwater is significantly influenced by traffic volume and the risk associated with stormwater from industrial areas is generally higher than that from commercial and residential areas. PMID:27046140

Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavymetals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavymetals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavymetals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavymetals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavymetal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavymetal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavymetals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavymetals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

Pure inorganic heavymetal ingestions for suicidal intent are a rare occurrence. Most case reports on this subject focus on the serious neurological, hepatic, or renal side effects. We describe two cases of significant heavymetal poisonings (arsenic trioxide and mercuric chloride) that were successfully managed with aggressive decontamination and combined chelation therapy. Both chemicals were obtained in pure powder form through the Internet. PMID:17394994

This work presents an optochemical dosimeter for determining and discriminating nickel, copper, and cobalt ions in water that can be used as an early warning system for water pollution. An inexpensive fiber optic spectrophotometer monitors the sensor's spectral behavior under exposure to water solutions of heavymetal ions in the 1-10 mg/l concentration range. The Principal Component Analysis (PCA) method quantitatively determines the heavymetals and discriminates their type and combination.

This report discusses the evaluation of the ENVIRO-CLEAN PROCESS, a technology developed by Lewis Environmental Services, Inc. for the recovery of metals such as chromium, mercury, copper, cadmium, lead, and zinc from surface and groundwater streams. This new heavymetal removal process (patent-pending) utilizes granular activated carbon with a proprietary conditioning pretreatment to enhance heavymetal adsorption combined with electrolytic metal recovery to produce a saleable metallic product. The process generates no sludge or hazardous waste and the effluent meets EPA limits. A 50 gpm system was installed for recovering hexavalent chromium from a ground water stream at a site located in Fresno, California. The effluent from the activated carbon system was reinjected into the ground water table with the hexavalent chromium concentration < 10 ppb. The system simultaneously removed trichloroethylene (TCE) to concentrations levels < 05 ppb. The activated carbon is regenerated off-site and the chromium electrolytically recovered. The full scale system has treated over 5 million gallons of ground water since installation. 5 refs., 1 fig., 3 tabs.

Eleven heavymetals in various products of Moringa oleifera were analyzed to determine eleven heavymetals (Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, and Zn) using Inductively Coupled Plasma-Mass Spectrometry. The products of M. oleifera were purchased in Nakhon Pathom, Thailand. All products were digested with nitric acid solution before determining the concentrations of heavymetals. The recoveries of all heavymetals were found to be in the range of 99.89-103.05%. Several criteria such as linearity, limits of detection, limits of quantification, specificity, precision under repeatability conditions and intermediate precision reproducibility were evaluated. Results indicate that this method could be used in the laboratory for determination of eleven heavymetals in M. oleifera products with acceptable analytical performance. The results of analysis showed that the highest concentrations of As, Cr, Hg, and Mn were found in tea leaves while the highest concentrations of Al, Cd, Cu, Fe, Ni, Pb, and Zn were found in leaf capsules. Continuous monitoring of heavymetals in M. oleifera products is crucial for consumer health. PMID:26664066

This paper presents results of a novel and state-of-the-art patent-pending processes developed jointly by Forrester Environmental Services Inc. (FESI) and Brookhaven National Laboratories (BNL) for the extraction and recovery of lead (Pb), Cadmium (Cd), Copper (Cu), Zinc (Zn) and other heavymetals from heavymetal bearing wastes including but not limited to solid waste incinerator bottom ash, flyash and combined ash. The heavymetal extraction and recovery processes were found to be capable of high percentage of heavymetals extraction and recovery at a relatively low cost under bench scale and full-scale refuse incinerator facility conditions. This paper presents empirical data from bench scale studies only, as the full-scale data is currently under review. The ash product remaining after extraction passed all TCLP regulatory limits and retained only minimal Pb, Cd, Cu, and Zn content and other water insoluble heavymetal compounds. Results of heavymetals recovery and low cost from ongoing field applications of this technology are consistent with the bench scale data presented within this paper.

Eleven heavymetals in various products of Moringa oleifera were analyzed to determine eleven heavymetals (Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, and Zn) using Inductively Coupled Plasma-Mass Spectrometry. The products of M. oleifera were purchased in Nakhon Pathom, Thailand. All products were digested with nitric acid solution before determining the concentrations of heavymetals. The recoveries of all heavymetals were found to be in the range of 99.89-103.05%. Several criteria such as linearity, limits of detection, limits of quantification, specificity, precision under repeatability conditions and intermediate precision reproducibility were evaluated. Results indicate that this method could be used in the laboratory for determination of eleven heavymetals in M. oleifera products with acceptable analytical performance. The results of analysis showed that the highest concentrations of As, Cr, Hg, and Mn were found in tea leaves while the highest concentrations of Al, Cd, Cu, Fe, Ni, Pb, and Zn were found in leaf capsules. Continuous monitoring of heavymetals in M. oleifera products is crucial for consumer health. PMID:26664066

This paper describes sorption and transport phenomena of selected heavymetals (e.g., Pb, Zn, Ni and Cu) in the superficial layer of soil and sewage sludge compost. The main aim of the study was the investigation of possibility of heavymetals contamination in soil profile reclaimed by sewage sludge compost. The column leaching test as well as the sequential Tessier extraction procedure were applied to investigate the mitigation of heavymetals. The results revealed that distribution of metals in specific Tessier fractions was the major factor influencing their transport in the investigated soils profiles. Moreover, sorption capacity of the soil sample studied was substantially greater to prevent transportation of metals into the lower horizons and groundwater. PMID:19241267

Heavymetal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavymetals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavymetal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots’ structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recoverheavymetals. PMID:26998896

Heavymetal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavymetals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavymetal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots' structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recoverheavymetals. PMID:26998896

Ultrasound has been found useful in increasing the efficiency and consumer safety in food processing. Removal of heavymetal (lead, mercury, and arsenic) contamination in milk is extremely important in regions of poor ecological environment - urban areas with heavy motor traffic or well established metallurgical/cement industry. In this communication, we report on the preliminary studies on the application of low frequency (20kHz) ultrasound for heavymetal decontamination of milk without affecting its physical, chemical, and microbiological properties. PMID:24746508

The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavymetals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavymetals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavymetals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavymetals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavymetals in the center of the soil specimen. PMID:27127923

Heavymetals combined with chlorinated solvents are one class of mixed waste found at various hazardous waste sites in North America. Nano zerovalent iron (nZVI), an emerging technology, is being successfully used for treating chlorinated solvents and heavymetals independently, however comparatively little research has investigated the remediation of the wastes when they are present in the same mixture. The remediation of trichloroethylene (TCE)/heavymetal waste mixtures via nZVI has been investigated in the present study. Results suggest that some metals are reduced by nZVI to their zerovalent state and thus precipitate on nZVI particles. This improves the contaminant removal performance of nZVI by forming bimetallic iron nanoparticles. Other metals are directly precipitated or adsorbed on the nZVI particles in their original oxidation state and are rendered immobile. In some cases the presence of the heavymetals in the waste mixture enhanced the dechlorination of TCE while in other cases it did not. This study suggests that nano zerovalent iron particles can be effectively used for the remediation of mixed contamination of heavymetals and chlorinated solvents. Results have been supported by a variety of techniques including X-ray photoelectron spectroscopy (XPS) analysis.

Tissue heavymetal concentrations in painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles from Lake Michigan coastal wetlands were analyzed to determine (1) whether turtles accumulated heavymetals, (2) if tissue metal concentrations were related to environmental metal concentrations, and (3) the potential for non-lethal sampling techniques to be used for monitoring heavymetal body burdens in freshwater turtles. Muscle, liver, shell, and claw samples were collected from painted and snapping turtles and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc. Turtle tissues had measurable quantities of all eight metals analyzed. Statistically significant correlations between tissue metal concentrations and sediment metal concentrations were found for a subset of metals. Metals were generally found in higher concentrations in the larger snapping turtles than in painted turtles. In addition, non-lethal samples of shell and claw were found to be possible alternatives to lethal liver and muscle samples for some metals. Human consumption of snapping turtles presents potential health risks if turtles are harvested from contaminated areas. Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems. PMID:26832725

A new approach to recovermetal values from spent lithium-ion batteries with a simple and environmentally friendly method is investigated. Two stages of water washing of the mixed black powder resulted in satisfactory separation of cobalt and lithium. Lithium in the wash liquor is precipitated using saturated sodium carbonate solution. Cobalt oxide in the residue is purified by removing organic matrix through roasting followed by dilute acid washing. The purities of the products obtained during the processes are analyzed by Microwave Plasma-Atomic Emission Spectrophotometer and confirmed from X-ray diffraction analysis. The overall process is safe, economic and can be scaled up for commercial production. Based on the process steps involved, a flow sheet is proposed for industrial application. PMID:26553316

This report describes a process for separating and concentrating heavymetals from electroplating rinse waters. Metal ions can be 'chemically pumped' across a coupled transport membrane against large concentration gradients by allowing the counterflow of a coupled ion such as hyd...

Uptake of heavymetals into hyperaccumulators is influenced by a number of chemical, physical and biological factors. Of these, recent evidence has shown that microbes living within the rhizosphere of hyperaccumulators may have a significant effect on metal uptake. Much is known about the role my...

Traditional sampling for heavymetal monitoring is a time-consuming and inconvenient method, which also does not indicate contaminants non-invasively and instantaneously. Moss is sensitive to heavymetals and is therefore considered a pollution indicator. However, it is unknown what kind physiological parameters can indicate metal contaminations quickly and non-invasively. Here, we systematically examined the effects of six heavymetals on physiological parameters and photosynthetic activities of two moss species grown in aquatic media or moist soil surface. We suggest that a phenotype with anthocyanin accumulation pattern and chlorosis pattern and two chlorophyll fluorescence parameters with their images can roughly reflect metal species groups, concentrations and differences between the two moss species. In other words, metal contaminations could be roughly estimated visually using the naked eye. Enzymatic and non-enzymatic anti-oxidative abilities and photosynthetic protein contents of Eurhynchium eustegium were higher than those of Taxiphyllum taxirameum, indicating their differential metal tolerance. Neither anti-oxidative abilities nor photosynthetic proteins were found to be ideal indicators. This study provides new ideas to monitor heavymetals rapidly and non-invasively in water or on wetland and moist soil surface. PMID:25919648

Lead, cadmium, mercury and arsenic are the most important heavymetals which may cause health risks following consumption of contaminated foods. Table salt is one the mostly used food additive with unique place in food consumption. Although purified table salt is expected to have lower level of contamination, some Iranians still prefer to use rock salt. Use of rock salt for food purposes has been banned by Iranian health authorities. In this study, heavymetal contamination of table salt consumed in Iran has been investigated. One hundred samples of rock and refined table salts were analyzed using atomic absorption spectrophotometeric methods for the presence of toxic heavymetals. The mean concentration of tested tracer metals including Cd, Pb, Hg and As was 0.024, 0.438, 0.021 and 0.094 μg/g, respectively. The concentrations of tested heavymetals were well below the maximum levels set by Codex. However, no statistically significant difference was found between contamination of rock salt and refined salt to heavymetals. PMID:24363718

A process for removing heavymetals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavymetal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavymetal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavymetal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavymetals from water using the process outlined above.

A process for removing heavymetals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavymetal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavymetal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavymetal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavymetals from water using the process outlined above.

Fuels like coal and rubber are frequently used for brick burning. However, both coal and rubber contain heavymetals. These heavymetals may elutriate in the wake of fly ash or may adsorb or absorb in the product. The present work deals with the analysis of heavymetals in some samples collected from brick burning industries located in the vicinity of a metropolitan city, Peshawar, Pakistan. Samples from raw clay, product, chimney scale and fossil fuel & rubber were collected and leached with acid mixture. The leachates were concentrated and analyzed by atomic absorption spectrophotometer for the determination of chromium (Cr), lead (Pb), cadmium (Cd) and antimony (Sb). It was observed that heavymetals are present in clay, brick and chimney scale. However, significant amount of these metals was observed in chimney scale. It is inferred that such emanations laden with heavymetals are accompanying the stack gases which are being dumped in to the environment. In order to avoid environmental problems, strict environmental regulations shall be enforced and a constant check on these emanations to the environment must be made to ensure clean air act. PMID:18853266

Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavymetals continuously released from various sources. Different heavymetals have been reported to generate adverse effects in many ways. Heavymetals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavymetals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavymetals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity. PMID:26618004

Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavymetals continuously released from various sources. Different heavymetals have been reported to generate adverse effects in many ways. Heavymetals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavymetals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavymetals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity. PMID:26618004

Vacuum metallurgy separation (VMS) is a technically feasible method to recover Pb, Cd and other heavymetals from crushed e-wastes. To further determine the environmental impacts and safety of this method, heavymetals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system are evaluated in this article. The mass concentrations of total suspended particulate (TSP) and PM10 are 0.1503 and 0.0973 mg m(-3) near the facilities. The concentrations of Pb, Cd and Sn in TSP samples are 0.0104, 0.1283 and 0.0961 μg m(-3), respectively. Health risk assessments show that the hazard index of Pb is 3.25 × 10(-1) and that of Cd is 1.09 × 10(-1). Carcinogenic risk of Cd through inhalation is 1.08 × 10(-5). The values of the hazard index and risk indicate that Pb and Cd will not cause non-cancerous effects or carcinogenic risk on workers. The noise sources are mainly the mechanical vacuum pump and the water cooling pump. Both of them have the noise levels below 80 dB (A). The thermal safety assessment shows that the temperatures of the vacuum metallurgy separation system surface are all below 303 K after adopting the circulated water cooling and heat insulation measures. This study provides the environmental information of the vacuum metallurgy separation system, which is of assistance to promote the industrialisation of vacuum metallurgy separation for recoveringheavymetals from e-wastes. PMID:25391553

The water hyacinth (Eichhornia crassipes) is a common aquatic plant in many tropical countries. Its ability absorb nutrients and other elements from the water has made it possible to use it for water purification purposes. Eichhornia, especially stems and leaves, have been successfully used as indicators of heavymetal pollution in tropical countries. The uptake of heavymetals in this plant is stronger in the roots than in the floating shoots. Metallothionein-like compounds have been found from roots of this species after cadmium exposure. The purpose of this investigation was to study the possibilities of using roots of water hyacinth as a biological indicator of metal pollution in tropical aquatic ecosystems.

The paper considers the problem of extreme toxicity heavymetal compounds dissolved in wastewater and liquid emissions of industrial enterprises to living organisms and environment as a whole. The possibility of increasing extraction efficiency of heavymetal ions by sorption materials was demonstrated. The porous space of the latter was modified by carbon nanotubes (CNTs) during process of the chemical vapour deposition (CVD) of carbon on metal oxide catalysts. The increasing of the sorption capacity (10-30%) and the sorption rate of nanomodified activated carbons in comparison with standard materials in the example of absorption of Co2+ and Ni2+ ions from aqueous solutions was proven.

For stabilization of heavymetals at contaminated sites, interaction of soil organic matter (SOM) with heavymetal ions is critically important for long-term sustainability, a factor that is poorly understood at the molecular level. Using 13C- and 15N-labeled soil humates (HS), we investigated the turnover of five organic amendments (celluose, wheat straw, pine shavings, chitin and bone meal) in relation to heavymetal ion leaching in soil column experiments. The labeled molecular substructures in HS were examined by multinuclear 2-D NMR and pyrolysis GC-MS while the element profile in the leachates was analyzed by ICP-MS. Preliminary analysis revealed that peptidic and polysaccharidic structures were highly enriched, which suggests their microbial origin. Cd(II) leaching was significantly attenuated with humification of lignocellulosic materials. Correlation of 13C and 15N turnovers of HS substructures to metal leaching is underway.

Various technologies are available to reclaim valuable, non-renewable metal resources from industrial wastes. Horsehead Resource Development Co. Inc. (HRD; Palmerton, PA.) employs several of these to recover such useful metals as zinc, lead and cadmium. Sources include a variety of wastestreams -- including electric-arc furnace (EAF) steel dusts, foundry dusts and sludges, wastewater treatment sludges, and electroplating wastes. The company processes between 350,000 and 400,000 tons of zinc-bearing wastes annually at six US processing plants, recovering and recycling about 75,000 tons of zinc, and 10,000 tons of lead and cadmium for industrial uses.

Pseudomonas aeruginosa is a ubiquitous, Gram-negative bacterium that utilizes several different modes of motility to colonize surfaces, including swarming, which is the coordinated movement of cells over surfaces in groups. Swarming facilitates surface colonization and biofilm development for P. aeruginosa, and it is known that swarming behavior is influenced by changes in nutrient composition and surface moisture. To understand the fate and cycling of heavymetals in the environment, it is important to understand the interaction and toxicity of these metals upon bacteria. While previous studies have shown surface-attached bacterial biofilms to be highly resistant to heavymetal toxicity, little is known about the influence of heavymetals upon surface motile bacteria and developing biofilms. Using a combination of laboratory assays we examined differences in bacterial behavior in response to two metals, Cd and Ni. We find that surface swarming bacteria are able to grow on 4x and 2.5x more Cd and Ni, respectively, than planktonic cells (i.e., test tube cultures). P. aeruginosa was able to swarm in the presence ≤0.051mM Ni and ≤0.045mM Cd. To investigate the bioavailability of metals to bacteria growing under our examined conditions, we separated cell and supernatant fractions of P. aeruginosa cultures, and used ICP-MS techniques to measure Cd and Ni sorption. A greater percentage of Cd than Ni was sorbed by both cells and supernatant (which contains rhamnolipid, a surfactant known to sorb some metals and improve swarming). While we show that cell products such as rhamnolipid bind heavymetals (as expected) and should limit metal bioavailability, our results suggest at least one additional mechanism (as yet undetermined) that promotes cell survival during swarming in the presence of these heavymetals.

Activity at Masaya volcano, Nicaragua, is characterised by periodic cycles of intense gas emission that last years to decades. The volcano entered its current phase of degassing in 1993, which resulted in a low-level persistent gas plume. As a result of this continuous emission, the substantial deposition of heavymetals onto the surrounding soils (andosols) is thought to be occurring (Delfosse et al., 2003). The deposition of these heavymetal plume components, and their incorporation into soil, is of key interest because once discharged to the environment they accumulate throughout the food chain and may pose a serious ecological threat (Alloway, 1995). Although many studies have focused on the impacts of volcanic gases on the environment, few have addressed the fate of the metals released by persistent gas plumes. This study therefore investigates the patterns of heavymetal transport, deposition and distribution at Masaya in order to provide additional information on the processes that govern the behaviour of volcanic heavymetals. A number of agricultural and non-agricultural soils at two horizons (A: 0-10 cm and B: 20-30 cm) were collected and their trace metal content analysed. Twenty sites were sampled from the active vent to ~5 km downwind, as well as two control sites upwind of the volcano. Preliminary data suggest that a rapid deposition of metals occurs close to the source, with metal concentrations in the soil generally decreasing with distance away from the active vent. Cr and As clearly follow this trend, with maximum concentrations of 20.71 and 7.61 mg/kg respectively occurring closest to the vent. Concentration peaks for Mn, Co, Ni, Cu, and Zn (959.30, 21.57, 13.44, 152.85, and 72.73 mg/kg respectively) occur slightly further away from the vent, implying that these metals are transported further. The concentration of Cr, Co, Al, Ni and Mn was found to increase from soil horizon A to B, whereas the abundance of Zn decreases with depth. Heavymetal

This study is to examine the influence of the metal components on the contents of heavymetals in composts of Municipal Solid Wastes (MSW). Fresh MSW used in composting was obtained from the city landfill of Taichung in Taiwan. Compost 1 was from as-collected MSW; Compost 2 was from degradable fraction in MSW; Compost 3 was from MSW without metal. The results show that the total concentration of zinc is the highest among the five heavymetals examined. Paper wastes are main sources of lead and copper with average concentrations of 18.53 mg/kg and 26.92 mg/kg of compost on dry weight. The contents of nickel and cadmium are relatively low. The total concentrations of the five heavymetals in composts increase by typical ratios between 1.72 and 2.58 for Composts 2 and 3, but 3.16 to 4.69 for Compost 1. The increase of concentration around a ratio of 2.0 is due to the loss of degraded organic matter. For the ratios above 2.0, fractions of some heavymetals have corroded from the surfaces of metal components into the Compost 1 in the early phase of acidic fermentation.

Heavymetals (Hg, Pb, Cd, Cu, Ni, Fe, Zn, and Mn) contents of the samples from 10 males were followed throughout a year. The values were characteristic of the individuals, and some correlations between the contents of different metals were shown.

Thlaspi caerulescens is a plant species capable of tolerating and accumulating extremely high concentrations of the heavymetals, Zn and Cd, in the shoot. In this study, we investigated the impact of changes in plant heavymetal status (i.e. Zn and Cd) on the accumulation of heavymetals, including...

Foshan is a ceramics manufacturing center in the world and the most polluted city in the Pearl River Delta (PRD) in southern China measured by the levels of atmospheric heavymetals. PM2.5 samples were collected in Foshan in winter 2008. Among the 22 elements and ions analyzed, 7 heavymetals (Zn, V, Mn, Cu, As, Cd and Pb) were studied in depth for their levels, spatiotemporal variations and sources. The ambient concentrations of the heavymetals were much higher than the reported average concentrations in China. The levels of Pb (675.7 ± 378.5 ng/m(3)), As (76.6 ± 49.1 ng/m(3)) and Cd (42.6 ± 45.2 ng/m(3)) exceeded the reference values of NAAQS (GB3095-2012) and the health guidelines of the World Health Organization. Generally, the levels of atmospheric heavymetals showed spatial distribution as: downtown site (CC, Chancheng District)>urban sites (NH and SD, Nanhai and Shunde Districts)>rural site (SS, Shanshui District). Two sources of heavymetals, the ceramic and aluminum industries, were identified during the sampling period. The large number of ceramic manufactures was responsible for the high levels of atmospheric Zn, Pb and As in Chancheng District. Transport from an aluminum industry park under light north-west winds contributed high levels of Cd to the SS site (Shanshui District). The average concentration of Cd under north-west wind was 220 ng/m(3), 20.5 times higher than those under other wind directions. The high daily maximum enrichment factors (EFs) of Cd, Pb, Zn, As and Cu at all four sites indicated extremely high contamination by local emissions. Back trajectory analysis showed that the heavymetals were also closely associated with the pathway of air mass. A positive matrix factorization (PMF) method was applied to determine the source apportionment of these heavymetals. Five factors (industry including the ceramic industry and coal combustion, vehicle emissions, dust, transportation and sea salt) were identified and industry was the most

To investigate the leaching and recovery of heavymetals from low-grade automobile shredder residue (ASR), the effects of nitric acid (HNO3) and hydrogen peroxide (H2O2) concentrations, liquid/solid (L/S) ratio, leaching temperature and ASR particle size fractions on the heavymetal leaching rate were determined. The heavymetals were recovered by fractional precipitation and advanced Fenton process (AFP) at different pHs. The toxicity characteristic leaching procedure (TCLP) test was also performed in the residue remaining after heavymetal leaching to evaluate the potential toxicity of ASR. The heavymetal leaching efficiency was increased with increasing HNO3 and H2O2 concentrations, L/S ratio and temperature. The heavymetal leaching efficiencies were maximized in the lowest ASR size fraction at 303 K and L/S ratio of 100 mL/g. The kinetic study showed that the metal leaching was best represented by a second-order reaction model, with a value of R(2) > 0.99 for all selected heavymetals. The determined activation energy (kJ/mol) was 21.61, 17.10, 12.15, 34.50, 13.07 and 11.45 for Zn, Fe, Ni, Pb, Cd and Cr, respectively. In the final residue, the concentrations of Cd, Cr and Pb were under their threshold limits in all ASR size fractions. Hydrometallurgical metal recovery was greatly increased by AFP up to 99.96% for Zn, 99.97% for Fe, 95.62% for Ni, 99.62% for Pb, 94.11% for Cd and 96.79% for Cr. AFP is highly recommended for the recovery of leached metals from solution even at low concentrations. PMID:26143080

Four kinds of amendments including humus, ammonium sulfate, lime, superphosphate and their complex combination were added to rapid immobilize the heavymetals in contaminated soils. The best material was chosen according to the heavymetals' immobilization efficiency and the Capacity Values of the fixative in stabilizing soil heavymetals. The redistributions of heavymetals were determined by the European Communities Bureau of Referent(BCR) fraction distribution experiment before and after treatment. The results were as follows: (1) In the single material treatment, lime worked best with the dosage of 2% compared to the control group. In the compound amendment treatments, 2% humus combined with 2% lime worked best, and the immobilization efficiency of Pb, Cu, Cd, Zn reached 98.49%, 99.40%, 95.86%, 99.21%, respectively. (2) The order of Capacity Values was lime > humus + lime > ammonium sulfate + lime > superphosphate > ammonium sulfate + superphosphate > humus + superphosphate > humus > superphosphate. (3) BCR sequential extraction procedure results indicated that 2% humus combined with 2% lime treatment were very effective in immobilizing heavymetals, better than 2% lime treatment alone. Besides, Cd was activated firstly by 2% humus treatment then it could be easily changed into the organic fraction and residual fraction after the subsequent addition of 2% lime. PMID:25898680

Objectives: This study aimed to obtain representative data on the levels of heavymetals in seafood and farm produce consumed by the general population in Uyo, Akwa Ibom State, Nigeria, a region known for the exploration and exploitation of crude oil. Methods: In May 2012, 25 food items, including common types of seafood, cereals, root crops and vegetables, were purchased in Uyo or collected from farmland in the region. Dried samples were ground, digested and centrifuged. Levels of heavymetals (lead, cadmium, nickel, cobalt and chromium) were analysed using an atomic absorption spectrophotometer. Average daily intake and target hazard quotients (THQ) were estimated. Results: Eight food items (millet, maize, periwinkle, crayfish, stock fish, sabina fish, bonga fish and pumpkin leaf) had THQ values over 1.0 for cadmium, indicating a potential health risk in their consumption. All other heavymetals had THQ values below 1.0, indicating insignificant health risks. The total THQ for the heavymetals ranged from 0.389 to 2.986. There were 14 items with total THQ values greater than 1.0, indicating potential health risks in their consumption. Conclusion: The regular consumption of certain types of farm produce and seafood available in Uyo, Akwa Ibom State, Nigeria, is likely adding to the body burden of heavymetals among those living in this region. PMID:26052462

With the development of researches, the treatments of wastewater have reached a certain level. Whereas, heavymetals in wastewater cause special concern in recent times due to their recalcitrance and persistence in the environment. Therefore, it is important to get rid of the heavymetals in wastewater. The previous studies have provided many alternative processes in removing heavymetals from wastewater. This paper reviews the recent developments and various methods for the removal of heavymetals from wastewater. It also evaluates the advantages and limitations in application of these techniques. A particular focus is given to innovative removal processes including adsorption on abiological adsorbents, biosorption, and photocatalysis. Because these processes have leaded the new trends and attracted more and more researches in removing heavymetals from wastewater due to their high efficency, pluripotency and availability in a copious amount. In general, the applicability, characteristic of wastewater, cost-effectiveness, and plant simplicity are the key factors in selecting the most suitable method for the contaminated wastewater. PMID:27318819

The existing practice of management of high level waste (HLW) generated by NPPs, call for a task of selective separation of the most dangerous long-lived radionuclides with the purpose of their subsequent immobilization and disposal. HLW partitioning allows to reduce substantially the cost of vitrified product storage owing to isolation of the most dangerous radionuclides, such as transplutonium elements (TPE) into separate fractions of small volumes, intended for ultimate storage. By now numerous investigations on partitioning of HLW of various composition have been carried out in many countries and a lot of processes permitting to recover cesium, strontium, TPE and rare earth elements (REE) have been already tested. Apart from enumerated radionuclides, a fair quantity of palladium and rhodium presents in spent fuel, but the problem of these elements recovery has not yet been decided at the operating radiochemical plants. A negative effect of platinum group metals (PGM) occurrence is determined by the formation of separate metal phase, which not only worsens the conditions of glass-melting but also shortens considerably the service life of the equipment. At the same time, the exhaustion of PGMs natural resources may finally lead to such a growth of their costs that the spent nuclear fuel would became a substituting source of these elements industrial production. Allowing above mentioned, it is of interest to develop the technique for ''reactor'' palladium and rhodium recovery process which would be compatible with HLW partitioning and could be realized using the same facilities. In the report the data on platinum metals distribution in spent fuel reprocessing products and the several flowsheets for palladium separation from HLW are presented.

Heavymetals such as cadmium, arsenic and nickel are classified as carcinogens. Although the precise mechanism of carcinogenesis is undefined, heavymetal exposure can contribute to genetic damage by inducing double strand breaks (DSBs) as well as inhibiting critical proteins from different DNA repair pathways. Here we take advantage of two previously published culture assay systems developed to address mechanistic aspects of DNA repair to evaluate the effects of heavymetal exposures on competing DNA repair outcomes. Our results demonstrate that exposure to heavymetals significantly alters how cells repair double strand breaks. The effects observed are both specific to the particular metal and dose dependent. Low doses of NiCl2 favored resolution of DSBs through homologous recombination (HR) and single strand annealing (SSA), which were inhibited by higher NiCl2 doses. In contrast, cells exposed to arsenic trioxide preferentially repaired using the “error prone” non-homologous end joining (alt-NHEJ) while inhibiting repair by HR. In addition, we determined that low doses of nickel and cadmium contributed to an increase in mutagenic recombination-mediated by Alu elements, the most numerous family of repetitive elements in humans. Sequence verification confirmed that the majority of the genetic deletions were the result of Alu-mediated non-allelic recombination events that predominantly arose from repair by SSA. All heavymetals showed a shift in the outcomes of alt-NHEJ repair with a significant increase of non-templated sequence insertions at the DSB repair site. Our data suggest that exposure to heavymetals will alter the choice of DNA repair pathway changing the genetic outcome of DSBs repair. PMID:26966913

Quiescently degassing volcanoes can significantly contribute to the global emission of heavymetals. In turn, substantial deposition of metals onto soils may result, possibly increasing the risk of phytotoxicity. In contrast to anthropogenic sources, the environmental impacts of airborne volcanic heavymetals and their accumulation in soils are poorly studied. Along with the degassing of S, Cl and F, Masaya volcano, Nicaragua, is also a strong source of heavymetals. Recent estimates indicate emission rates of e.g., 62 t As yr-1, 133 t Zn yr-1 and 306 t Cu yr-1 (Moune, 2002). Here, we report on the effects of heavymetal depositions on the total contents of As, Cr, Ni, Cu, Bi, Zn, Se, and Co in two groups of soils located 5 km and 15 km downwind from the volcano. These soils correspond to young Vitric Andosols and more weathered Eutric Andosols, respectively. As and Se were measured by Inductively Coupled Plasma-Atomic Emission Spectrometry after soil digestion in a trace metal unit, and Cr, Ni, Cu, Co, Bi and Zn were determined after alkaline fusion in Li-metaborate/Li-tetraborate. Results suggest that prolonged metal inputs in the vicinity of Masaya volcano have significantly increased the As, Se and Zn contents of the soils. For these elements, concentrations are about 3-5 times those measured in the parent rock materials. However, maximum concentrations in soils (i.e., 5.4 mg As kg-1, 183 mg Zn kg-1 and 0.9 mg Se kg-1) never exceed critical concentration levels as defined for cultivated soils in the UK (10, 300 and 3 mg kg-1 for As, Zn and Se, respectively). We did not detect significant enrichments in Cr, Ni, Cu, Bi, and Co. The relatively low accumulation of metals in the Masaya Andosols contrasts with the high retention of volcanic F and S inputs (Delmelle et al., 2003). Since Andosols typically show a high affinity for heavymetals, which can be bound to organic matter as well as to oxides, oxyhydroxide and allophane minerals present in these soils, rapid

Community level toxicity tests were conducted in outdoor experimental streams to examine the responses of aquatic insects to heavymetals. Introduced substrates (plastic trays filled with small cobble) were colonized at several locations in a river impacted by heavymetals. After 30 d, 4delta trays from an upstream control site were transferred to 12 outdoor experimental streams. Each stream was randomly assigned to one of three treatments: control, low metals, and high metals. Two trays were removed from each stream after 4 and 10 d exposure. Community structure on these trays was compared to field data collected from control and impacted sites. Macroinvertebrate density and number of taxa were reduced in both treated streams and at impacted field sites. Owing to differences in relative sensitivity to metals, the percent composition of dominant taxa also varied among treatments.

Heavymetals become toxic when they are not metabolized by the body and accumulate in the soft tissue. Chelation therapy is mainly for the management of heavymetal-induced toxicity; however, it usually causes adverse effects or completely blocks the vital function of the particular metal chelated. Much attention has been paid to the development of chelating agents from natural sources to counteract lead- and iron-induced hepatic and renal damage. Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of proinflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels. Because metal chelating therapy is associated with adverse effects, treating heavymetal toxicity in addition with sesame oil and sesamol may be better alternatives. This review deals with the possible use and beneficial effects of sesame oil and sesamol during heavymetal toxicity treatment. PMID:23744838

In this study, bioleaching was coupled with electrokinetics (BE) to remove heavymetals (Cu, Zn, Cr and Pb) from contaminated soil. For comparison, bioleaching (BL), electrokinetics (EK), and the chemical extraction method were also applied alone to remove the metals. The results showed that the BE method removed more heavymetals from the contaminated soil than the BL method or the EK method alone. The BE method was able to achieve metal solubilization rates of more than 70 % for Cu, Zn and Cr and of more than 40 % for Pb. Within the range of low current densities (<1 mA cm(-2)), higher current density led to more metal removal. However, the metal solubilization rates did not increase with increasing current density when the current density was higher than 1 mA cm(-2). Therefore, it is suggested that bioleaching coupled with electrokinetics can effectively remediate heavymetal-contaminated soils and that preliminary tests should be conducted before field operation to detect the lowest current density for the greatest metal removal. PMID:25680933

The efficiency of heavymetal removal from soil by EDTA leaching was assessed in a column leaching experiment at the laboratory scale and field heap leaching at the pilot scale using a sandy loam sierozem agricultural soil contaminated with Cd, Cu, Pb, and Zn. Soil amendment and aging were conducted to recover leaching soils. The percentages of Cd, Cu, Pb, and Zn removed by column leaching were 90%, 88%, 90%, and 67%, respectively, when 3.9 bed volumes of 50mM EDTA were used. At the pilot scale, on-site metal removal efficiencies using the selected leaching procedure were 80%, 69%, 73% and 62% for Cd, Cu, Pb and Zn, respectively. EDTA leaching decreased soil CEC, total P, total K and available K concentrations but increased organic matter and total Kjeldahl N concentrations. The subsequent amendment and soil aging further reduced the DTPA-extractable heavymetals in the leached soils. Growth of the first crop of pak choi in the leached soil was inhibited but the second crop grew well after the soil was aged for one year and the concentrations of Cd and Pb in the edible parts were below the Chinese statutory limits. The results demonstrate the potential feasibility of the field leaching technique using EDTA combined with subsequent amendment and soil aging for the remediation of heavymetal-contaminated agricultural soils. PMID:25277965

Several species from the Brassica genus are very important agricultural crops in different parts of the world and are also known to be heavymetal accumulators. There have been a large number of studies regarding the tolerance, uptake and defense mechanism in several of these species, notably Brassica juncea and B. napus, against the stress induced by heavymetals. Numerous studies have also been published about the capacity of these species to be used for phytoremediation purposes but with mixed results. This review will focus on the latest developments in the study of the uptake capacity, oxidative damage and biochemical and physiological tolerance and defense mechanisms to heavymetal toxicity on six economically important species: B. juncea, B. napus, B. oleracea, B. carinata, B. rapa and B. nigra. PMID:26247945

In order to study heavymetal pollution in dustfall during Winter in North China, forty-four dustfall samples were collected in North China Region from November 2013 to March 2014. Then forty trace elements content were measured for each sample by inductively coupled plasma-mass spectrometry. Finally, the contamination characteristics of the main heavymetals were studied through a multi-method analysis, including variability analysis, Pearson correlation analysis and principal component analysis. Results showed that the relative contents of cadmium (Cd), zinc (Zn), copper (Cu), bismuth (Bi), lead (Pb) exceeded the standards stipulated in Chinese soil elements background values by amazing 4.9 times. In this study, conclusions were drawn that dustfall heavymetal pollution in the region was mainly caused by transport pollution, metallurgy industrial pollution, coal pollution and steel industrial pollution. PMID:26215458

Baker's yeast (Saccharomyces cerevisiae) is microorganism which is commercially available and sold as packaged dry pellets in any food store at low cost. Studies have been undertaken on the effects of organic xenobiotics as well as heavymetals on yeast metabolism. This type of study has been generally useful in examining the mechanism(s) of chemical toxicity. However, a rapid and quantitative toxicity test using S. cerevisiae as the test organism has not been developed. The purpose of this study was to develop a toxicity assay for heavymetals, using commercial dry yeast as the test microorganism. This rapid and simple procedure is based on the reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) to INT-formazan by the yeast electron transport system. The scoring of active cells following exposure to heavymetals was undertaken according to the MINT (malachite green-INT) method developed by Bitton and Koopman.

Data on the bulk contents of heavymetals in polluted soils are not quite suitable to judge the ecological situation in an agrocenosis. According to the results of model experiments with artificial contamination of soil, the flux of zinc and lead from the starting point (from a medium loamy leached chernozem) to the final point (wheat grains) sharply decreases. It is possible to obtain an ecologically pure (uncontaminated) grain yield even on a strongly contaminated soil due to the buffering capacity of the latter and due to the self-protective capacity of agricultural crops. The ecological potential of the soil-crop system is formed mostly at the expense of the buffering capacity of soil to heavymetals; the barrier function of plants is less significant. It is argued that the existing ecological standards based on the total contents of heavymetals in soil are of little use for predicting the quality of crops.

Several species from the Brassica genus are very important agricultural crops in different parts of the world and are also known to be heavymetal accumulators. There have been a large number of studies regarding the tolerance, uptake and defense mechanism in several of these species, notably Brassica juncea and B. napus, against the stress induced by heavymetals. Numerous studies have also been published about the capacity of these species to be used for phytoremediation purposes but with mixed results. This review will focus on the latest developments in the study of the uptake capacity, oxidative damage and biochemical and physiological tolerance and defense mechanisms to heavymetal toxicity on six economically important species: B. juncea, B. napus, B. oleracea, B. carinata, B. rapa and B. nigra. PMID:26247945

The purpose of this research is the basic study for the development of separation technology of heavymetal compounds from hot flue gas. While the hot flue gas containing heavymetals from a melting furnace of industrial waste passes through the high temperature dust collector which can be varied the operating temperature. The heavymetals can be separated due to different boiling point of each heavymetal. On the basis of this concept, the concentration of heavymetals in the flue gas were sampled and measured at inlet, outlet of the ceramic filter housing in the actual industrial waste processing system. Speciation of heavymetals in collected ashes was clarified by separating heavymetals according to compounds using their elution characteristics. Moreover, equilibrium analysis was performed to determine the effect of temperature, flue gases conditions on heavymetals speciation, and it was compared with experimental data. From these results, we discussed about separation performance of heavymetal compounds by hot gas cleaning.

The topsoil around Beijing metropolis, China, is experiencing impacts of rapid urbanization, intensive farming, and extensive industrial emissions. We analyzed the concentrations of Cu, Ni, Pb, Zn, Cd, and Cr from 87 topsoil samples in the pre-rainy season and 115 samples in the post-rainy season. These samples were attributed to nine land use types: forest, grass, shrub, orchard, wheat, cotton, spring maize, summer maize, and mixed farmland. The pollution index (PI) of heavymetals was calculated from the measured and background concentrations. The ecological risk index (RI) was assessed based on the PI values and toxic-response parameters. The results showed that the mean PI values of Pb, Cr, and Cd were > 1 while those of Cu, Ni, and Zn were < 1. All the samples had low ecological risk for Cu, Ni, Pb, Zn, and Cr while only 15.35% of samples had low ecological risk for Cd. Atmospheric transport rather than land use factors best explained the seasonal variations in heavymetal concentrations and the impact of atmospheric transport on heavymetal concentrations varied according to the heavymetal types. The concentrations of Cu, Cd, and Cr decreased from the pre- to post-rainy season, while those of Ni, Pb, and Zn increased during this period. Future research should be focused on the underlying atmospheric processes that lead to these spatial and seasonal variations in heavymetals. The policymaking on environmental management should pay close attention to potential ecological risks of Cd as well as identifying the transport pathways of different heavymetals. PMID:27159454

These six metals, commonly classified as heavymetals, are a subset of a larger group of trace elements that occur in low concentration in the Earth's crust. These heavymetals were mined extensively for use in the twentieth century Industrial Society. Nriagu (1988a) estimated that between 0.5 (Cd) and 310 (Cu) million metric tons of these metals were mined and ultimately deposited in the biosphere. In many instances, the inputs of these metals from anthropogenic sources exceed the contributions from natural sources (weathering, volcanic eruptions, forest fires) by several times ( Adriano, 1986). In this chapter, heavymetals (elements having densities greater than 5) and trace elements (elements present in the lithosphere in concentrations less than 0.1%) are considered synonymous.It has been observed in the past that the rate of emission of these trace metals into the atmosphere is low due to their low volatility. However, with the advent of large-scale metal mining and smelting as well as fossil-fuel combustion in the twentieth century, the emission rate of these metals has increased dramatically. As most of these emissions are released into the atmosphere where the mammals live and breathe, we see a great increase in the occurrence of health problems such as lead (Pb) poisoning, cadmium (Cd) Itai-itai disease, chromium (Cr), and nickel (Ni) carcinogenesis.In this chapter, the author has attempted to present a synopsis of the importance of these metals in the hydrocycle, their natural and anthropogenic emissions into the environment, their prevalent geochemical form incorporated into lacustrine sediments, and their time-trend distributions in watersheds that have been impacted by urbanization, mining and smelting, and other anthropogenic activities. These time trends are reconstructed from major-minor-trace-element distributions in age-dated sediment cores, mainly from reservoirs where the mass sedimentation rates (MSRs) are orders of magnitude greater than

The objective of this work is to assess heavymetals fixation capacity on sonicated activated sludge. Ultrasonic treatment of sludge has lead to its desintegration and changes physico-chemical characteristics such as soluble chemical oxygen demand, proteins or particle size distribution. This study has shown that these modifications have improved significantly the capacity of sludge to fix heavymetals. Indeed, after a sonication of 15 min and storage of three days after irradiation, the equilibrium capacity is increased about 45%. The restructuration of sludge during the storage seems to increase the accessibility to active binding sites. PMID:18599337

Brassinosteroids (BRs) are a widespread group of plant hormones. These phytohormones play a crucial role in the regulation of growth and development of various plant species, and they demonstrate high biological activity. BRs are considered to demonstrate protective activity in the plants exposed to various stresses. Due to rapid industrialization and urbanization, heavymetals have become one of the most important plant stressors. In plants, accumulation of heavymetals beyond the critical levels leads to oxidative stress. However, BRs may inhibit the degradation of lipids, resulted from the overproduction of reactive oxygen species under stress conditions, and increase the activity of antioxidants. They also have the ability to promote phytochelatins synthesis. PMID:27242833

Many industries discharge untreated wastewater into the environment. Heavymetals from many industrial processes end up as hazardous pollutants of wastewaters.Heavymetal pollution has increased in recent decades and there is a growing concern for the public health risk they may pose. To remove heavymetal ions from polluted waste streams, adsorption processes are among the most common and effective treatment methods. The adsorbents that are used to remove heavymetal ions from aqueous media have both advantages and disadvantages. Cost and effectiveness are two of the most prominent criteria for choosing adsorbents. Because cost is so important, great effort has been extended to study and find effective lower cost adsorbents.One class of adsorbents that is gaining considerable attention is agricultural wastes. Among many alternatives, palm oil biomasses have shown promise as effective adsorbents for removing heavymetals from wastewater. The palm oil industry has rapidly expanded in recent years, and a large amount of palm oil biomass is available. This biomass is a low-cost agricultural waste that exhibits, either in its raw form or after being processed, the potential for eliminating heavymetal ions from wastewater. In this article, we provide background information on oil palm biomass and describe studies that indicate its potential as an alternative adsorbent for removing heavymetal ions from wastewater. From having reviewed the cogent literature on this topic we are encouraged that low-cost oil-palm-related adsorbents have already demonstrated outstanding removal capabilities for various pollutants.Because cost is so important to those who choose to clean waste streams by using adsorbents, the use of cheap sources of unconventional adsorbents is increasingly being investigated. An adsorbent is considered to be inexpensive when it is readily available, is environmentally friendly, is cost-effective and be effectively used in economical processes. The

The optical and physical characteristics of heavymetal fluoride glasses are reviewed with reference to recent laboratory experiments. In particular, attention is given to comparative optical studies of fluorozirconate and fluorohafnate glasses, refractive index and material dispersion of fluoride glasses, and preliminary results of optical studies of heavymetal fluoride glasses not containing ZrF4 or HfF4. The latter sometimes exhibit extended transparency in the mid-IR relative to that observed in fluorozirconate and fluorohafnate glasses. The effect of the AlF4 content on the optical properties of BaF2/ThF4 glasses is discussed.

Brassinosteroids (BRs) are a widespread group of plant hormones. These phytohormones play a crucial role in the regulation of growth and development of various plant species, and they demonstrate high biological activity. BRs are considered to demonstrate protective activity in the plants exposed to various stresses. Due to rapid industrialization and urbanization, heavymetals have become one of the most important plant stressors. In plants, accumulation of heavymetals beyond the critical levels leads to oxidative stress. However, BRs may inhibit the degradation of lipids, resulted from the overproduction of reactive oxygen species under stress conditions, and increase the activity of antioxidants. They also have the ability to promote phytochelatins synthesis. PMID:27242833

Heavymetal pollution, as well as greenhouse effect, has become a serious threat today. Both heavymetal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavymetals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavymetals. Heavymetals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavymetal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavymetal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavymetals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavymetals. In addition, germination that was inhibited by high concentrations of heavymetals was also partly reversed by fluridone. The obtained results support the idea that heavymetal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not. PMID:27239687

Ionic liquids are expected to replace conventional organic solvents in organic synthesis, solvent extraction and electrochemistry due to their unique characters such as low volatility, high stability and so on. In this work, N,N,-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide was used as an alternative solvent to extract heavymetal ions. As the extracting conditions, the additional effect of 8-hydroxyquinoline (8-HQ) as metal chelating agent into ionic liquids, shaking time and volume ratio were investigated. As extraction efficiency depended on 8-HQ concentration significantly, in order to extract high concentrated metal ions the solubility of 8-HQ into ionic liquid was tested. N,N,-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide had good solubility of 8-HQ. Consequently, 5 μmol of copper, zinc, cadmium and manganese could be completely recovered with 100 μl of ionic liquid.

Speciation can fundamentally affect on the stability and toxicity of heavymetals in sludge from wastewater treatment plants. This research investigated the speciation of heavymetals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavymetal speciation. The results show that the drying process generally stabilized the Cr, Cu, Cd and Pb in sludge by transforming acid-soluble, reducible and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavymetals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.

Although the direct combustion of biomass for energy that applies circulating fluidized bed (CFB) technology is steadily expanding worldwide, only few studies have conducted an environmental assessment of biomass ash thus far. Therefore, this study aims to integrate information on the environmental effects of biomass ash. We investigated the concentration of heavymetal in biomass ash samples (bottom ash, cyclone ash, and filter ash) derived from a CFB boiler that combusted agricultural and forest residues at a biomass power plant (2×12 MW) in China. Ash samples were gathered for the digestion and leaching test. The heavymetal content in the solution and the leachate was studied via an inductively coupled plasma-mass spectrometer and a Malvern Mastersizer 2000 mercury analyzer. Measurements for the chemical composition, particle size distribution, and the surface morphology were carried out. Most of the metals in cyclone ash particles were enriched, whereas Ti and Hg were enriched in filter ash. Residence time contributed most to heavymetal enrichment. Under HJ/T 300 conditions, the heavymetals showed serious leaching characteristics. Under EN 12457-2 conditions, leaching behavior was hardly detected. PMID:22840499

Toxic heavymetals emitted by industrial activities in the midlatitudes are transported through the atmosphere and deposited in the polar regions; bioconcentration and biomagnification in the food chain mean that even low levels of atmospheric deposition may threaten human health and Arctic ecosystems. Little is known about sources and long-term trends of most heavymetals before approximate to 1980, when modern measurements began, although heavy-metal pollution in the Arctic was widespread during recent decades. Lacking detailed, long-term measurements until now, ecologists, health researchers, and policy makers generally have assumed that contamination was highest during the 1960s and 1970s peak of industrial activity in North America and Europe. We present continuous 1772-2003 monthly and annually averaged deposition records for highly toxic thallium, cadmium, and lead from a Greenland ice core showing that atmospheric deposition was much higher than expected in the early 20th century, with tenfold increases from preindustrial levels by the early 1900s that were two to five times higher than during recent decades. Tracer measurements indicate that coal burning in North America and Europe was the likely source of these metals in the Arctic after 1860. Although these results show that heavy-metal pollution in the North Atlantic sector of the Arctic is substantially lower today than a century ago, contamination of other sectors may be increasing because of the rapid coal-driven growth of Asian economies.

This study employed Jatropha curcas (bioenergy crop plant) to assist in the removal of heavymetals from contaminated field soils. Analyses were conducted on the concentrations of the individual metals in the soil and in the plants, and their differences over the growth periods of the plants were determined. The calculation of plant biomass after 2 years yielded the total amount of each metal that was removed from the soil. In terms of the absorption of heavymetal contaminants by the roots and their transfer to aerial plant parts, Cd, Ni, and Zn exhibited the greatest ease of absorption, whereas Cu, Cr, and Pb interacted strongly with the root cells and remained in the roots of the plants. J. curcas showed the best absorption capability for Cd, Cr, Ni, and Zn. This study pioneered the concept of combining both bioremediation and afforestation by J. curcas, demonstrated at a field scale. PMID:25236867

This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (<88%) when conducted in pH values higher than 1. Thus, sequential use of NF and RO was proved to be a promising treatment for sulfuric acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water. PMID:27438241

Chelating agents are added to soil as a means to mobilize heavymetals for plant uptake during phytoremediation. Yet almost no studies follow the displacement of heavymetals through the vadose zone following solubilization with chelating agents. The objective of this work was to determine the movement of heavymetals through the soil profile and their absorption by barley (Hordeum vulgare L.) in a soil amended with biosolids and in the presence of a chelating agent (EDTA). Twelve columns 75 cm in height and 17 in diameter were packed with a Haynie very fine sandy loam (coarse-silty, mixed, calcareous, mesic Mollic Udifluvents) and watered with liquid biosolids applied at the surface at a rate of 120 kg N/ha. Three weeks after plants germinated, soil was irrigated with a solution of the disodium salt of EDTA added at a rate of 0.5 g/kg soil. Four treatments were imposed: columns with no plants and no EDTA; columns with no plants plus EDTA; columns with plants and no EDTA; and columns with plants and EDTA. Columns were watered intensively for 35 days until two pore volumes of water had been added, and the leachates were collected daily. With or without plants, columns with EDTA had lower total concentrations of Cu, Zn, Cd, Ni, and Pb in the surface 20 cm than columns without EDTA. Concentrations of the heavymetals in this layer were not afffected by the presence of roots. Iron in leachate was followed as an indicator metal for movement to groundwater. No iron appeared in the leachate without EDTA, either in the columns with plants or without plants. The peak concentration of iron in the leachate occurred three days earlier in the columns without plants and EDTA compared to the columns with plants and EDTA. The results indicated the importance of vegetation on retarding heavymetal leaching to groundwater during chelate-facilitated phytoremediation.

Bioremediation of wastewater containing heavymetals is one of the major challenges in environmental biotechnology. Heavymetals are not degraded and as a result they remain in the ecosystem, and pose serious health hazards as it comes in contact with human due to anthropogenic activities. Biological treatment with various microorganisms has been practiced widely in recent past, however, accessing and maintaining the microorganisms have always been a challenge. Microorganisms like Baker's yeast can be very promising biosorbents as they offer high surface to volume ratio, large availability, rapid kinetics of adsorption and desorption and low cost. The main aim of this study is to evaluate the applicability of the biosorption process using baker's yeast. Here we present an experimental investigation of biosorption of Chromium (Cr) from water using commercial Baker's Yeast. It was envisaged that yeast, dead or alive, would adsorb heavymetals, however, operating parameters could play vital roles in determining the removal efficiency. Parameters, such as incubation time, pH, amount of biosorbent and heavymetal concentration were varied to investigate the impacts of those parameters on removal efficiency. Rate of removal was found to be inversely proportional to the initial Cr (+6) concentrations but the removal rate per unit biomass was a weakly dependent on initial Cr(+6) concentrations. Biosorption process was found to be more efficient at lower pH and it exhibited lower removal with the increase in solution pH. The optimum incubation time was found to be between 6-8 hours and optimum pH for the metal ion solution was 2. The effluents produced in leather industries are the major source of chromium pollution in Bangladesh and this study has presented a very cost effective yet efficient heavymetal removal approach that can be adopted for such kind of wastewater.

Release and distribution of heavymetals through industrial wastewaters has adverse affects on the environment via contamination of surface- and ground-water resources. Biosorption of heavymetals from aqueous solutions has been proved to be very promising, offering significant advantages such as low cost, availability, profitability, ease of operation, and high efficiency, especially when dealing with low concentrations. Residual biomasses of industrial microorganisms including bacteria, algae, fungi, and yeast have been found to be capable of efficiently accumulating heavymetals as biosorbent. This paper presents and investigates major mechanisms of biosorption and most of the functional groups involved. The biosorption process includes the following mechanisms: transport across cell membrane, complexation, ion exchange, precipitation, and physical adsorption. In order to understand how metals bind to the biomass, it is essential to identify the functional groups responsible for metal binding. Most of these groups have been characterized on the cell walls. The biosorbent contains a variety of functional sites including carboxyl, imidazole, sulfydryl, amino, phosphate, sulfate, thioether, phenol, carbonyl, amide, and hydroxyl moieties that are responsible for metal adsorption. These could be helpful to improve biosorbents through modification of surface reactive sites via surface grafting and/or exchange of functional groups. PMID:24804650

Heavymetals including mercury, lead, and cadmium are present throughout the ecosystem and are detectable in small amounts in the Great Lakes water and fish. The main route of exposure of humans to these metals is via the ingestion of contaminated food, especially fish. Extensive experimental investigations indicated that heavymetals alter a number of parameters of the host's immune system and lead to increased susceptibility to infections, autoimmune diseases, and allergic manifestations. The existing limited epidemiologic data and data derived from in vitro systems in which human peripheral blood leukocytes were used suggested that the human immune system may also be at increased risk following exposure to these metals. The magnitude of the risk that the presence of such metals in the Great Lakes may pose to the human immune system, and consequently to their health, is not known. In this review, the available data with respect to potential adverse effects of heavymetals on the immune system of humans and experimental animals are discussed, and additional data requirements are suggested. PMID:8635436

The toxicity of heavymetals is well documented today and legislation for their control in seawater continuously becomes more and more restrictive. In order to control and ensure the marine environment quality it is demanded an effort to develop new analytical tools, which allow the analysis of trace levels of heavymetals in seawater. The measurement of luminescence (phosphorescence and fluorescence) gives rise to high sensitive, selective and innovative approaches which could be used to develop new trace metal sensing methods. In this way, we have observed that the metal-chelates formed between different sulphonic-hydroxyquinolines with heavymetals, such as lead, or the metal-chelates between mercury and purines exhibit strong room temperature phosphorescence and fluorescence, respectively. Based on the formation of such quelates, two luminescence methods are investigated for sensing of lead and mercury in seawater. Optimum experimental conditions and the analytical performance characteristics of the methods are discussed. Relative standard deviations in the order of 4% are typical at 100 ng mL-1 of Pb(II) and Hg (II). The detection limits are 0.1 and 1.4 ng mL-1 for lead and mercury, respectively. Possible interferences present in seawater, including sea water cations and anions are evaluated in detail. Finally, the methods are applied to the determination de mercury and lead in seawater samples.

Sewage sludge ash (SSA) is a prospective phosphorus source for the future production of recycling P-fertilizers. Due to its high heavymetals contents and the relatively low P plant-availability, SSA must be treated before agricultural utilisation. In this paper SSA was thermochemically treated with PVC in a bench-scale rotary furnace in order to remove heavymetals via the chloride pathway. PVC has a high Cl-content of 52-53% and a high heating value that can be beneficially used for the thermochemical process. Large amounts of waste PVC are already recovered in recycling processes, but there are still some fractions that would be available for the proposed thermochemical process, for example, the low quality near-infrared(NIR)-fraction from waste separation facilities. Heavymetals were effectively removed at temperatures in the range of 800-950 °C via the gas phase by utilisation of PVC as Cl-donor. The resulting P plant-availability was comparable to SSA thermochemically treated with MgCl(2) as Cl-donor if MgO was used as an additive (Mg-donor). A further increase of the plant availability of phosphorus was achieved by acid post-treatment of the thermochemically treated SSA. PMID:23189972

Stenotrophomonas maltophilia is an aerobic, non-fermentative Gram-negative bacterium widespread in the environment. S. maltophilia Sm777 exhibits innate resistance to multiple antimicrobial agents. Furthermore, this bacterium tolerates high levels (0.1 to 50 mM) of various toxic metals, such as Cd, Pb, Co, Zn, Hg, Ag, selenite, tellurite and uranyl. S. maltophilia Sm777 was able to grow in the presence of 50 mM selenite and 25 mM tellurite and to reduce them to elemental selenium (Se0) and tellurium (Te0) respectively. Transmission electron microscopy and energy dispersive X-ray analysis showed cytoplasmic nanometer-sized electron-dense Se0 granules and Te0 crystals. Moreover, this bacterium can withstand up to 2 mM CdCl2 and accumulate this metal up to 4% of its biomass. The analysis of soluble thiols in response to ten different metals showed eightfold increase of the intracellular pool of cysteine only in response to cadmium. Measurements by Cd K-edge EXAFS spectroscopy indicated the formation of Cd-S clusters in strain Sm777. Cysteine is likely to be involved in Cd tolerance and in CdS-clusters formation. Our data suggest that besides high tolerance to antibiotics by efflux mechanisms, S. maltophilia Sm777 has developed at least two different mechanisms to overcome metal toxicity, reduction of oxyanions to non-toxic elemental ions and detoxification of Cd into CdS. PMID:18253487

Human activity resulting in heavymetal contamination is a worldwide concern. Lead is a potent neurotoxin that can cause heart problems, kidney damage, and mental retardation. Mercury causes toxicity based on its form and route of exposure. Effects range from allergic reactions t...

Concentration of heavymetals (Cd, Ni, Zn, Fe, Cu, Mn, Pb, Cr, Hg and As) in the waters of River Yamuna and in the soil of agricultural fields along its course in Delhi are reported from 13 sites, spread through the Delhi stretch of Yamuna, starting from the Wazirabad barrage till the Okhla barrage. Varying concentration of heavymetals was found. Peaks were observed in samples collected downstream of Wazirabad and Okhla barrage, indicating the anthropogenic nature of the contamination. The Wazirabad section of the river receives wastewater from Najafgarh and its supplementary drains, whereas the Shahdara drain releases its pollution load upstream of the Okhla barrage. Average heavymetal concentration at different locations in the river water varied in the order of Fe>Cr>Mn>Zn>Pb>Cu>Ni>Hg>As>Cd. The river basin soil shows higher level of contamination with lesser variation than the water samples among sampling locations, thereby suggesting deposition over long periods of time through the processes of adsorption and absorption. The average heavymetal concentration at different locations in soil varied in the order of Fe>Mn>Zn>Cr>Pb>Ni>Hg>Cu>As>Cd. PMID:21505769

Case reports of individuals taking Ayurvedic herbal medicine products (HMPs) suggest that they may contain lead, mercury, and/or arsenic. We analyzed the heavymetal content of Ayurvedic HMPs manufactured in India and Pakistan, available in South Asian grocery stores in the Bost...

A mpilot-scale permeable reactive wall consisting of a leaf-rich compost-pea gravel mixture was installed at a site in the Vancouver area, Canada to evaluate its potential use for treatment of a large dissolved heavymetal plume. The compost based permeable reactive wall promote...

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavymetals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavymetal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavymetals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavymetals originated several times and by different mechanisms in Streptomyces history. PMID:23247041

The town of Bor (Serbia) is one of the most polluted towns in southeastern Europe. The copper smelter which is situated in the centre of the town is the main pollutant, mostly because of its old technology, which leads to environmental pollution caused by higher concentrations of SO 2 and PM 10. These facts show that the word is about a very polluted region in Europe which, apart from harming human health in the region itself, poses a particular danger for wider area of southeastern Europe. Optimization of heavymetal's total emission was undertaken because years of long contamination of the soil with heavymetals of anthropogenic origin created a danger that those heavymetals may enter the food chains of animals and people, which can lead to disastrous consequences. This work represents the usage of Geographic Information System (GIS) for establishing a multifactor assessment model to quantitatively divide polluted zones and for selecting control sites in a linear programming model, combined with PROMETHEE/GAIA method, Screen View modeling system, and linear programming model. The results show that emissions at some control sites need to be cut for about 40%. In order to control the background of heavymetal pollution in Bor, the ecological environment must be improved.

The Taimyr Peninsula is directly north of the world's largest heavymetal smelting complex (Norilsk, Russia). Despite this proximity, there has been little research to examine the extent of contamination of the Taimyr Peninsula, primarily because of the remoteness of this area. W...

Attitudes and characteristics of adolescents who like heavymetal music (HMM) were explored in a study of 52 adolescents (largely White males) who liked HMM and 123 who did not in suburban Atlanta (Georgia). HMM is discussed as a reflection of, rather than a cause of, adolescent alienation. (SLD)

Elevated concentrations of heavymetals in edible plants could expose consumers to excessive levels of potentially hazardous chemicals. Sixty-three accessions (genotypes) of Capsicum chinense Jacq, collected from 8 countries of origin, were grown in a silty-loam soil under field conditions. At matur...

Chemical remediation of soil may involve the use of harsh chemicals that generate waste streams, which may adversely affect the soil's integrity and ability to support vegetation. This article reviews the potential use of benign reagents, such as biopolymers, to extract heavymetals. The biopolymers discussed are chitin and chitosan, modified starch, cellulose, and polymer-containing algae. (Copyright (c) Remediation 1994.)

Analyses of eggs of three species of North American accipitrine hawks for organochlorines and heavymetals indicate that contamination with DDE may be the primary cause of recent population declines of two of the species, Cooper's hawk and sharp-shinned hawk.

Heavymetals and agrochemicals are the key targets for biochar-induced mitigation of runoff/groundwater contamination. Inorganic and organic contaminants interact differently with biochars as well as soil components. Mechanistic understandings are needed on sorption, desorption, and competitive sor...

Within the last decade, a novel form of microbial metabolism of major environmental significance has been elucidated. In this process, known as dissimilatory metal reduction, specialized microorganisms, living in anoxic aquatic sediments and ground water, oxidize organic compounds to carbon dioxide with metals serving as the oxidant. Recent studies have demonstrated that this metabolism explains a number of important geochemical phenomena in ancient and modern sedimentary environments, affecting not only the cycling of metals but also the fate of organic matter. Furthermore, this metabolism may have practical application in remediation of environments contaminated with toxic metals and/or organics.

This paper seeks to think creatively about the body of research which claims there is a link between heavymetal music and adolescent alienation, self-destructive behaviours, self-harm and suicide. Such research has been criticised, often by people who belong to heavymetal subcultures, as systematically neglecting to explore, in a meaningful manner, the psychosocial benefits for individuals who both listen to contemporary heavymetal music and socialize in associated groups. We argue that notions of survival, strength, community, and rebellion are key themes in contemporary heavymetal music. Through literary-lyrical analysis of a selection of heavymetal tracks, this paper aims to redress the balance of risk and benefit. We argue that listening to this type of music, the accompanying social relationships, sense of solidarity and even the type of dancing can ameliorate tumultuous and difficult emotions. Songs which could be read as negative can induce feelings of relief through the sense that someone else has felt a particular way and recovered enough to transform these emotions into a creative outlet. This genre of music may therefore not increase the risk of untoward outcomes in any simple sense but rather represent a valuable resource for young people in difficulty. PMID:24682627

A method is described for separating plutonium from aqueous acidic solutions of neutron-irradiated uranium and the impurities associated therewith. The separation is effected by adding, to the solution containing hexavalent uranium and plutonium, acetate ions and the ions of an alkali metal and those of a divalent metal and thus forming a complex plutonium acetate salt which is carried by the corresponding complex of uranium, such as sodium magnesium uranyl acetate. The plutonium may be separated from the precipitated salt by taking the same back into solution, reducing the plutonium to a lower valent state on reprecipitating the sodium magnesium uranyl salt, removing the latter, and then carrying the plutonium from ihe solution by means of lanthanum fluoride.

We studied the efficiency of water treatment by water hyacinth (Eichhornia crassipes) from heavymetals (Zn, Cd, Pb, Cu), as well as a possibility of using water hyacinth biomass obtained during treatment for vermicomposting by Eisenia fetida and the vermicompost quality in a model experiment. The results showed that the concentration of heavymetals in the trials with water hyacinth decreased within 35 days. We introduced water hyacinth biomass to the organic substrate for vermicomposting, which promoted a significant weight gain of earthworms and growth in their number, as well as a 1.5- to 3-fold increase in coprolite production. In the trial with 40 % of Eichhornia biomass in the mixture, we observed a 26-fold increase in the number and a 16-fold weight gain of big mature individuals with clitellum; an increase in the number of small individuals 40 times and in the number of cocoons 140 times, as compared to the initial substrate. The utilization of water hyacinth biomass containing heavymetals in the mixture led to a 10-fold increase in the number of adult individuals and cocoons, which was higher than in control. We found out that adding 10 % of Eichhornia biomass to the initial mixture affected slightly the number of microorganisms and their species diversity in the vermicompost. Adding Eichhornia biomass with heavymetals reduced the total number of microorganisms and sharply diminished their species diversity. In all trials, adding water hyacinth in the mixture for vermicomposting had a positive impact on wheat biometric parameters in a 14-day laboratory experiment, even in the trial with heavymetals. PMID:25501861

We report on an optical cuvette test for total heavymetals based on the inhibition of the enzyme urease by metals ions including silver(I), mercury(II), copper(II), nickel(II), cobalt(II), and cadmium(II). The enzymatic action is monitored using an optical ammonia transducer deposited on the wall of a disposable cuvette. This results in a rapid and inexpensive single-shot device for heavymetal sensing. A solution of urease and buffer is placed in the cuvette with the ammonium sensor membrane fixed on one of its walls. Enzymatic action starts after addition of a defined quantity of urea. This is indicated by the increase in the absorption of the ammonia sensor membrane whose color changes from yellow to blue. The slop of the increase in signal is the information for the un-inhibited reaction. After several minutes,the sample (containing the heavymetal) is added to the cuvette. Heavymetal ions inhibit the enzyme (by binding to the sulfhydryl groups) and cause a decrease in the slope. The ratio of slopes of un-inhibited and inhibited reactions is a direct parameter for detecting and calculating total heavymetals. The optimum pH was a trade-off between optimum enzyme activity (pH 7 at 25 degree(s)C) and the relative signal change of the ammonia-sensor (highest at pH 8). pH 7.5 was found to be optimal. The system was calibrated at optimized activities of urease (1.5 (mu) ) and an optimized urea concentration (0.5 mmol). Heavymetals inhibit in the following order: Ag(I) > Hg(II) > Cu(II) >> Ni(II) > Co(II) > Cd(II) > Fe(III) > Pb(II), Zn(II). The following concentrations that cause 50% inhibition were found: Ag(I) (0.1 ppm), Hg(II) (0.5 ppm), Cu(II) (0.5 ppm), Ni(II) (7 ppm), Co(II) (30 ppm), Cd(II) (95 ppm), Fe(III) (50 ppm), Zn(II) (85 ppm) and Pb(II) (210 ppm). We also studied the inhibitory effect of combinations of metal ions, the influence of ionic strength, and the effect of incubation time.

Illegal e-waste recycling activity has caused heavymetal pollution in many developing countries, including China. In recent years, the Chinese government has strengthened enforcement to impede such activity; however, the heavymetals remaining in the abandoned e-waste recycling site can still pose ecological risk. The present study aimed to investigate the concentrations of heavymetals in soil and water in the vicinity of an abandoned e-waste recycling site in Longtang, South China. Results showed that the surface soil of the former burning and acid-leaching sites was still heavily contaminated with Cd (>0.39 mg kg(-1)) and Cu (>1981 mg kg(-1)), which exceeded their respective guideline levels. The concentration of heavymetals generally decreased with depth in both burning site and paddy field, which is related to the elevated pH and reduced TOM along the depth gradient. The pond water was seriously acidified and contaminated with heavymetals, while the well water was slightly contaminated since heavymetals were mostly retained in the surface soil. The use of pond water for irrigation resulted in considerable heavymetal contamination in the paddy soil. Compared with previous studies, the reduced heavymetal concentrations in the surface soil imply that heavymetals were transported to the other areas, such as pond. Therefore, immediate remediation of the contaminated soil and water is necessary to prevent dissemination of heavymetals and potential ecological disaster. PMID:25460954

Ten sites along the Tecate River, Mexico were sampled to evaluate the cadmium, lead, nickel and chromium concentrations in sediments. The result shows contamination for cadmium in most of the sites, where two sites were class 4 (polluted to strongly polluted) according to geoaccumulation index proposed by Muller. Two sites were found polluted for all the heavymetals analyzed (Cr, Cd, Pb and Ni), indicating the effect of anthropogenic activities. A correlation between Ni and Cd concentration had been found indicating a common source. These metals are usually used in electroplating industry. The results of this study can be used for decision makers to prioritize measures to control the pollution for these metals.

The use of dead, dried aquatic plants, for water removal of metals derived from industrial activities as a simple biosorbent material has been increasing in the last years. The mechanism of simultaneous metal removal (Cd2+, Ni2+, Cu2+, Zn2+ and Pb2+) by 3 macrophytes biomass (Spirodela intermedia, Lemna minor and Pistia stratiotes) was investigated. L. minor biomass presented the highest mean removal percentage and P. stratiotes the lowest for all metals tested. Pb2+ and Cd2+ were more efficiently removed by the three of them. The simultaneous metal sorption data were analysed according to Langmuir and Freundlich isotherms. Data fitted the Langmuir model only for Ni and Cd, but Freundlich isotherm for all metals tested, as it was expected. The K(F) values showed that Pb was the metal more efficiently removed from water solution. The adsorption process for the three species studied followed first order kinetics. The mechanism involved in biosorption resulted ion exchange between monovalent metals as counter ions present in the macrophytes biomass and heavymetal ions and protons taken up from water. No significant differences were observed in the metal exchange amounts while using multi-metal or individual metal solutions. PMID:15990152

To fully exploit the environmental benefits of the biogas process, the digestate should be recycled as biofertiliser to agriculture. This practice can however be jeopardized by the presence of unwanted compounds such as heavymetals in the digestate. By using two-stage digestion, where the first stage includes hydrolysis/acidification and liquefaction of the substrate, heavymetals can be transferred to the leachate. From the leachate, metals can then be removed by adsorption. In this study, up to 70% of the Ni, 40% of the Zn and 25% of the Cd present in maize was removed when the leachate from hydrolysis was circulated over a macroporous polyacrylamide column for 6 days. For Cu and Pb, the mobilization in the hydrolytic stage was lower which resulted in a low removal. A more efficient two-stage process with improved substrate hydrolysis would give lower pH and/or longer periods with low pH in the hydrolytic stage. This is likely to increase metal mobilisation, and would open up for an excellent opportunity of heavymetal removal. PMID:18359995

Highly negatively charged particles were fabricated via an innovative plasma-assisted approach for the removal of heavymetal ions. Thiophene plasma polymerization was used to deposit sulfur-rich films onto silica particles followed by the introduction of oxidized sulfur functionalities, such as sulfonate and sulfonic acid, via water-plasma treatments. Surface chemistry analyses were conducted by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Electrokinetic measurements quantified the zeta potentials and isoelectric points (IEPs) of modified particles and indicated significant decreases of zeta potentials and IEPs upon plasma modification of particles. Plasma polymerized thiophene-coated particles treated with water plasma for 10 min exhibited an IEP of less than 3.5. The effectiveness of developed surfaces in the adsorption of heavymetal ions was demonstrated through copper (Cu) and zinc (Zn) removal experiments. The removal of metal ions was examined through changing initial pH of solution, removal time, and mass of particles. Increasing the water plasma treatment time to 20 min significantly increased the metal removal efficiency (MRE) of modified particles, whereas further increasing the plasma treatment time reduced the MRE due to the influence of an ablation mechanism. The developed particulate surfaces were capable of removing more than 96.7% of both Cu and Zn ions in 1 h. The combination of plasma polymerization and oxidative plasma treatment is an effective method for the fabrication of new adsorbents for the removal of heavymetals. PMID:25603034

Accumulation of heavymetals by algae had been studied extensively for biomonitoring or bioremediation purposes. Having the advantages of low cost raw material, big adsorbing capacity, no secondary pollution, etc., algae may be used to treat industrial water containing heavymetals. The adsorption processes were carried out in two steps: rapid physical adsorption first, and then slow chemical adsorption. pH is the major factor influencing the adsorption. The Freundlich equation fitted very well the adsorption isotherms. The uptake decreased with increasing ionic strength. The principal mechanism of metallic cation sequestration involves the formation of complexes between a metal ion and functional groups on the surface or inside the porous structure of the biological material. The carboxyl groups of alginate play a major role in the complexation. Different species of algae and the algae of the same species may have different adsorption capacity. Their selection affinity for heavymetals was the major criterion for the screening of a biologic adsorbent to be used in water treatment. The surface complex formation model (SCFM) can solve the equilibrium and kinetic problems in the biosorption.

Between their many applications bismuth nanoparticles (BiNPs) are showing interest as pre-concentrators in heavymetals detection while being applied as working electrode modifiers used in electrochemical stripping analysis. From the different reported methods to synthesize BiNPs we are focused on the typical polyol method, largely used in these types of metallic and semi-metallic nanoparticles. This study presents the strategy for an easy control of the shape and size of BiNPs including nanocubes, nanosferes and triangular nanostructures. To improve the BiNP size and shape, different reducing agents (ethylene glycol or sodium hypophosphite) and stabilizers (polyvinyl pyrrolidone, PVP, in different amounts) have been studied. The efficiency of BiNPs for heavymetals analysis in terms of detection sensitivity while being used as modifiers of screen-printed carbon electrodes including the applicability of the developed device in real sea water samples is shown. A parallel study between the obtained nanoparticles and their performance in heavymetal sensing has been described in this communication. PMID:25994368

Heavymetals in urban stormwater runoff are primarily removed by sedimentation in stormwater best management practices (BMPs) such as constructed wetlands. Heavymetals accumulated in wetland sediments may be potentially toxic to benthic invertebrates and aquatic microorganisms, ...

This project concerns the development of immunoassays for heavymetals that will permit the rapid on-site analysis of specific heavymetals, including lead and chromium in water and soil samples. 2 refs.

We have developed a fluorescence resonance energy transfer (FRET)-based heavymetal biosensor for the quantification of bioavailable free heavymetals in the cytoplasm of the microalga Chlamydomonas reinhardtii. The biosensor is composed of an end-to-end fusion of cyan fluorescent protein (CFP), chicken metallothionein II (MT-II), and yellow fluorescent protein (YFP). In vitro measurements of YFP/CFP fluorescence emission ratios indicated that the addition of metals to the purified biosensor enhanced FRET between CFP and YFP, consistent with heavymetal-induced folding of MT-II. A maximum YFP/CFP FRET ratio of 2.8 was observed in the presence of saturating concentrations of heavymetals. The sensitivity of the biosensor was greatest for Hg2+ followed by Cd2+ ≈ Pb2+ > Zn2+ > Cu2+. The heavymetal biosensor was unresponsive to metals that do not bind to MT-II (Na+ and Mg2+). When expressed in C. reinhardtii, we observed a differential metal-dependent response to saturating external concentrations (1.6 mm) of heavymetals (Pb2+ > Cd2+) that was unlike that observed for the isolated biosensor (in vitro). Significantly, analysis of metal uptake kinetics indicated that equilibration of the cytoplasm with externally applied heavymetals occurred within seconds. Our results also indicated that algae have substantial buffering capacity for free heavymetals in their cytosol, even at high external metal concentrations. PMID:24368336

Heavymetal pollution is a principle source of environmental contamination. We analyzed heavymetal impacted soil microbial communities and found that, in general, although lead adversely affected biomass, metabolic activity, and diversity, autochthonous lead- and cadmium-resistant isolates were found. In several metal-stressed soils, the microbial community consisted of two populations, either resistant or sensitive to lead. Additionally, a lead-resistant isolate was isolated from a control soil with no known previous exposure to lead, suggesting widespread lead resistance. Lead-resistant genera isolated included Pseudomonas, Bacillus, Corynebacterium, and Enterobacter species. Plasmids, ranging from 5 to 260 kb, were not detected through standard purifications from lead-resistant isolates. Positive correlations existed between antibiotic resistance and isolation habitat for lead-resistant strains, microbial metabolic activity and soil type, soluble lead concentration and microbial diversity, and arsenic concentration and total or viable cell concentrations. PMID:8801006

This article presents a low-cost portable electrochemical instrument capable of on-site identification of heavymetals. The instrument acquires metal-specific voltage and current signals by the application of differential pulse anodic stripping voltammetry. This technique enhances the analytical current and rejects the background current, resulting in a higher signal-to-noise ratio for a better detection limit. The identification of heavymetals is based on an intelligent machine-based method using a multilayer perceptron neural network consisting of three layers of neurons. The neural network is implemented using a 16 bit microcontroller. The system is developed for use in the field in order to avoid expensive and time-consuming procedures and can be used in a variety of situations to help environmental assessment and control.

This study is based on the investigation of the performance of electrocoagulation (EC), followed by the microfiltration process for heavymetal removal in synthetic model waste water containing Zn2+, Ni2+ and Cd2+ ions. Effects of initial concentration, current density and pH on metal removal were analysed to optimize the EC process. The optimized EC process was then integrated with dead-end microfiltration (MF) and was found that the hybrid process was capable of 99% removal of heavymetals. The cake layer formed over the membrane by the hybrid process was analysed through scanning electron microscope-energy-dispersive X-ray spectroscopy. The particle size analysis of the sludge formed during EC was done to investigate the fouling caused during the process. PMID:24527655

Heavymetal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavymetals and their toxicity mechanisms, along with their health effects. PMID:26109881

Phytoremediation potential of L. minor for cadmium (Cd), copper (Cu), lead (Pb), and nickel (Ni) from two different types of effluent in raw form was evaluated in a glass house experiment using hydroponic studies for a period of 31 days. Heavymetals concentration in water and plant sample was analyzed at 3, 10, 17, 24, and 31 day. Removal efficiency, metal uptake and bio-concentration factor were also calculated. Effluents were initially analyzed for physical, chemical and microbiological parameters and results indicated that municipal effluent (ME) was highly contaminated in terms of nutrient and organic load than sewage mixed industrial effluent (SMIE). Results confirmed the accumulation of heavymetals within plant and subsequent decrease in the effluents. Removal efficiency was greater than 80% for all metals and maximum removal was observed for nickel (99%) from SMIE. Accumulation and uptake of lead in dry biomass was significantly higher than other metals. Bio-concentration factors were less than 1000 and maximum BCFs were found for copper (558) and lead (523.1) indicated that plant is a moderate accumulator of both metals. Overall, L. minor showed better performance from SMIE and was more effective in extracting lead than other metals. PMID:26114480

Unprecedented bioaccumulation and biomagnification of heavymetals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavymetal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants. PMID:25688377

Unprecedented bioaccumulation and biomagnification of heavymetals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavymetal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants. PMID:25688377

Heavymetals present in tannery sludge can get mobilized in the environment in various forms and can be a cause for concern for the natural ecosystem and human health. The speciation of metals in sludge provides valuable information regarding their toxicity in the environment and determines their suitability for land application or disposal in landfills. Concentrations of seven heavymetals (Cr, Pb, Cd, Ni, Zn, As and Cu) in tannery sludge were determined to evaluate their toxicity levels. Metal contents ranged over the following intervals: As: 1.52-2.07 mg/kg; Pb: 57.5-67 mg/kg; Cr: 15339-26501 mg/kg; Cu: 261.3-579.5 mg/kg; Zn: 210.2-329.1 mg/kg and Ni: 137.5-141.3 mg/kg (dry weight basis). The concentrations of all heavymetals in the sludge samples were lower compared to EPA guidelines except chromium which was found to be several orders of magnitude higher than the guideline value. Toxicity Characteristics Leaching Procedure (TCLP) test indicated that the leaching potential of chromium was higher compared to the other heavymetals and exceeded the EPA land disposal restriction limits. To quantitatively assess the environmental burden of the chromium associated with tannery sludge, the IMPACT 2002+ methodology was adopted under the SimaPro software environment. Considering the USEPA limit for chromium as the baseline scenario, it was found that chromium in the tannery sludge had 6.41 times higher impact than the baseline in the categories of aquatic ecotoxicity, terrestrial ecotoxicity and non-carcinogens. Chromium has the highest contribution to toxicity in the category of aquatic ecotoxicity while copper is the major contributor to the category of terrestrial ecotoxicity in the tannery sludge.

Heavymetals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavymetal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavymetals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavymetals intake by human populations through food chain has been reported in many countries. Soil threshold for heavymetal toxicity is an important factor affecting soil environmental capacity of heavymetal and determines heavymetal cumulative loading limits. For soil-plant system, heavymetal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavymetals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavymetal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavymetal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavymetal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavymetals, thus influencing the thresholds for assessing dietary toxicity of heavymetals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavymetals in vegetables and food crops and assesses soil heavymetal thresholds for potential dietary

Heavymetals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavymetal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavymetals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavymetals intake by human populations through food chain has been reported in many countries. Soil threshold for heavymetal toxicity is an important factor affecting soil environmental capacity of heavymetal and determines heavymetal cumulative loading limits. For soil-plant system, heavymetal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavymetals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavymetal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavymetal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavymetal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavymetals, thus influencing the thresholds for assessing dietary toxicity of heavymetals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavymetals in vegetables and food crops and assesses soil heavymetal thresholds for potential dietary

Wood ash contains important amounts of heavymetals. This quantity depends on burned specie, temperature of exposition and heat duration time. Due the high mineralization imposed by the temperatures, ash is used as lime product in agriculture and forests. Also, after a forest fire large quantities of ash are produced and distributed in soil surface. This mineralized organic matter can induce important environmental problems, including soil toxicity provoked by heavymetals leachates from ash. There is an extensive literature about heavymetals contents on ash in different species. However, it recently highlighted that the same species placed in different environments can respond diversely to same temperatures. This question is of major importance because temperature effects on severity can be a function of the plant communities instead of specie characteristics. These findings add a higher degree of complexity in the understanding of temperature effects on ash composition and consequent availability of heavymetals. The aim of this study is to compare the ash chemical heavymetal composition, Cobalt (Co), Chromium (Cr), Cooper (Cu), Silver (Ag), Lead (Pb), Nickel (Ni), Manganese (Mn) and Zinc (Zn), from Pinus sylvestris and Betula pendula, collected in key and representative areas of Lithuanian forests, located in southern, coastal and central part. Samples were collected from alive trees, taken to laboratory and air dried. Subsequently were crushed and submitted to muffle furnace at temperature of 550°C during two hours. The ash samples were digested and in a HNO3-HCl solution and then analysed with AAS. Comparisons between species and sites were performed with a Non-parametric one-way ANOVA‘s on rank transformed data followed by Tukey‘s HSD, significant at a p<0.05. Results showed significant difference between Co and Ag concentrations between Pinus sylvestris and Betula pendula. Also, significantly different concentrations of Pb, Cu, Ni and Mn were

In this paper, wood waste (RWW) recovered for heat production in Sweden was studied. Previous research has concluded that RWW contains elevated amounts of heavymetals, causing environmental problems during waste management. This study extends previous work on RWW by analysing which pollution sources cause this contamination. Using existing data on the metal contents in various materials, and the amounts of these materials in RWW, the share of the elevated amounts of metals in RWW that these materials explain was quantified. Six different materials occurring in RWW were studied and the results show that they explain from 70% to 100% of the amounts of arsenic, chromium, lead, copper and zinc in RWW. The most important materials contributing to contamination of RWW are surface-treated wood, industrial preservative-treated wood, plastic and galvanised fastening systems. These findings enable the development and evaluation of strategies aiming to decrease pollution and resource loss from handling RWW. It is argued that source separation and measures taken further downstream from the generation site, such as treatment, need to be combined to substantially decrease the amount of heavymetals in RWW.

Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water and air. In recent years, phytoremediation assisted by bacterial endophytes has been highly recommended for cleaning up of metal polluted soils since endophytic bacteria can alleviate metal toxicity in plant through their own metal resistance system and facilitate plant growth under metal stress. Endophytic bacteria improve plant growth in metal polluted soils in two different ways: 1) directly by producing plant growth beneficial substances including solubilization/transformation of mineral nutrients (phosphate, nitrogen and potassium), production of phytohormones, siderophores and specific enzymes; and 2) indirectly through controlling plant pathogens or by inducing a systemic resistance of plants against pathogens. Besides, they also alter metal accumulation capacity in plants by excreting metal immobilizing extracellular polymeric substances, as well as metal mobilizing organic acids and biosurfactants. The present work aims to review the progress of recent research on the isolation, identification and diversity of metal resistant endophytic bacteria and illustrate various mechanisms responsible for plant growth promotion and heavymetal detoxification/phytoaccumulation/translocation in plants. PMID:26989941

The Tessier sequential extraction method was employed to investigate the changes in heavymetals speciation (Zn, Cu, Mn, Fe, Pb, Ni, Cd and Cr) during water hyacinth (Eichhornia crassipes) composting. Results showed that, the contents of total metals concentration were increased during the composting process. The largest proportion of metals was found in the residual fraction which was in more stable form and is consequently considered unavailable for plant uptake. Reducible and oxidizable fractions of Ni, Pb and Cd were not found in all trials during water hyacinth composting. The concentrations of Cu and Cd were very low comparative to the other metals, but the percentage of exchangeable and carbonate fractions were similar as other metals. From this study it can be concluded that the appropriate proportion of cattle manure addition (Trial 4) significantly reduced the mobile and easily available fractions (exchangeable and carbonate fractions) during the composting process. PMID:22989643

Tire dust is a significant pollutant, especially as a source of zinc in the urban environment. This study characterizes the morphology and chemical composition of heavymetal particles embedded in tire dust and traffic-related materials (brake dust, yellow paint, and tire tread) as measured by a field emission scanning electron microscope equipped with an energy dispersive X-ray spectrometer (FESEM/EDX). In 60 samples of tire dust, we detected 2288 heavymetal particles, which we classified into four groups using cluster analysis according to the following typical elements: cluster 1: Fe, cluster 2: Cr/Pb, cluster 3: multiple elements (Ti, Cr, Fe, Cu, Zn, Sr, Y, Zr, Sn, Sb, Ba, La, Ce, Pb), cluster 4: ZnO. According to their morphologies and chemical compositions, the possible sources of each cluster were as follows: (1) brake dust (particles rich in Fe and with trace Cu, Sb, and Ba), (2) yellow paint (CrPbO(4) particles), (3) brake dust (particulate Ti, Fe, Cu, Sb, Zr, and Ba) and heavy minerals (Y, Zr, La, and Ce), (4) tire tread (zinc oxide). When the chemical composition of tire dust was compared to that of tire tread, the tire dust was found to have greater concentrations of heavymetal elements as well as mineral or asphalt pavement material characterized by Al, Si, and Ca. We conclude that tire dust consists not only of the debris from tire wear but also of assimilated heavymetal particles emitted from road traffic materials such as brake lining and road paint. PMID:15337346

A review of the literature dealing with the biological accumulation and toxicity of heavymetals in aquatic ecosystems is presented. The review first examines the sources of heavymetals and the process of ecological concentration of these pollutants. The biological effects of cadmium, copper, and zinc on fish and invertebrates are considered in detail. Methods of detoxification of heavymetals are presented. (KRM)

Owing to the Industrial Revolution in the late 1970s, heavymetal pollution has been regarded as a serious threat to mangrove ecosystems in the region of the Pearl River Estuary, potentially affecting human health. The present study attempted to characterize the ecological risk of heavymetals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in Nansha mangrove, South China, by estimating their concentrations in the surface sediment. In addition, the pollution history of heavymetals was examined by determining the concentrations of heavymetals along the depth gradient. The phytoremediation potential of heavymetals by the dominant plants in Nansha mangrove, namely Sonneratia apetala and Cyperus malaccensis, was also studied. Results found that the surface sediment was severely contaminated with heavymetals, probably due to the discharge of industrial sewage into the Pearl River Estuary. Spatial variation of heavymetals was generally unobvious. The ecological risk of heavymetals was very high, largely due to Cd contamination. All heavymetals, except Mn, decreased with depth, indicating that heavymetal pollution has been deteriorating since 1979. Worse still, the dominant plants in Nansha mangrove had limited capability to remove the heavymetals from sediment. Therefore, we propose that immediate actions, such as regulation of discharge standards of industrial sewage, should be taken by the authorities concerned to mitigate the ecological risk posed by heavymetals. PMID:24675443

The soils of the urban environment, owing to the various anthropogenic activities, can be contaminated by heavymetals. The traffic is well-known for more decades to be main source of heavymetals mostly in cities. The accumulation of these elements can have different effects, either directly endangering the natural soil functions, or indirectly endangering the biosphere by bio-accumulation and inclusion in the food chain. The hobby gardens and the vegetable gardens directly along roads can be potential risky for people since unknown amount of heavymetals can be accumulated into organization of local residents due to consumption of vegetables and fruits grown in their own garden. The aim of this study was to determine the heavymetal content of garden soils directly along roads with heavy traffic in order to assess possible risk for human health. The total content and the mobile content of Cd, Co, Cr, Cu, Ni, Pb and Zn have been determined in samples from garden soils along 5 busy roads of Szeged, South Hungary. Enrichment factor has been calculated with the help of control soil samples far from roads. The soil properties basically influencing on metal mobility have also been examined. Finally, the human health risk of these garden soils has been modelled by determination of health risk quotient (HRQ). As a result of our investigations, it can be claimed that mostly Cu, Zn and to a lesser degree the Ni, Cr and Pb accumulated in garden soils along roads depending on the traffic density. In general, the topsoils (0-10 cm) had higher amount of these metals rather than the subsoils (40-50 cm). Ni of these metals has approached; Cu has exceeded limit value while Pb is under it. Cd is very high in both soils along roads and control ones far from roads. Garden soils along the roads have such basic soil parameters (pH, mechanical soil type, humus content) that prove fairly high metal-binding capacity for these soils. Total risk of usage of these gardens (ingestion of soil

This article evaluates adsorption ability of the altered bituminous coals to remove heavymetals and/or phenol from aqueous solutions. As for heavymetals, copper (II), cadmium (II) and lead (II) cations were used. In addition to phenol, cyclohexanol and 2-cyclohexen-1-ol were also examined. Adsorption experiments were conducted in the batch mode at room temperature and at pH 3 and 5. To characterize the texture of coal samples, adsorption isotherms of nitrogen at - 196{sup o}C, enthalpies of the immersion in water, and pH values in aqueous dispersions were measured. Coal hydrogen aromaticities were evaluated from the infrared spectrometric examinations (DRIFTS). Based on the investigations performed, cation exchange was confirmed as the principal mechanism to immobilize heavymetallic ions on coals. However, apart from carboxylic groups, other functionalities (hydroxyl groups) were found to be involved in the adsorption process. During adsorption of phenol, {pi}-{pi} interactions between {pi}-electrons of phenol and aromatic rings of coal proved to play the important role; however, no distinct correlation between adsorption capacities for phenol and hydrogen aromaticities of the coal was found. Probable involvement of oxygenated surface groups in the immobilization of phenol on coal was deduced. As a result, for waste water treatment, oxidative altered bituminous coal can be recommended as a suitable precursor, with the largest immobilization capacities both for metallic ions and phenol, as found in the studied samples.

Heavymetals, which have severe toxic effects on plants, animals, and human health, are serious pollutants of the modern world. Remediation of heavymetal pollution is utmost necessary. Among different approaches used for such remediation, phytoremediation is an emerging technology. Research is in progress to enhance the efficiency of this plant-based technology. In this regard, the role of rhizospheric and symbiotic microorganisms is important. It was assessed by enumeration of data from the current studies that efficiency of phytoremediation can be enhanced by assisting with diazotrophs. These bacteria are very beneficial because they bring metals to more bioavailable form by the processes of methylation, chelation, leaching, and redox reactions and the production of siderophores. Diazotrophs also posses growth-promoting traits including nitrogen fixation, phosphorous solubilization, phytohormones synthesis, siderophore production, and synthesis of ACC-deaminase which may facilitate plant growth and increase plant biomass, in turn facilitating phytoremediation technology. Thus, the aim of this review is to highlight the potential of diazotrophs in assisting phytoremediation of heavymetals in contaminated soils. The novel current assessment of literature suggests the winning combination of diazotroph with phytoremediation technology. PMID:25339525

Copper smelting in Sarcheshmeh copper complex poses a serious threat to soil contamination by toxic heavymetals (As, Cu, Mo, Cd, Pb, Zn). In this study assessment of induced pollution to soil is carried out and heavymetal speciation is investigated. Calculated geoaccumulation index (Igeo) using baseline values in control site indicate that the most polluted stations are those close to the smelter and also in the prevailing wind directions. Also the level of contamination is rapidly decreased with increasing distance from the smelter. This is in agreement with statistical results and soil pollution index (SPI) which also confirm decreasing elemental concentration with increasing distance from the smelter. Sequential extraction analyses indicate that metal mobility is not significant and the exchangeable fraction is negligible in most cases. The results of mobility factor calculation reflect decreasing heavymetal mobility with depth and also distance from the smelter. Furthermore, residual fraction constitutes a major fraction especially in the case of Pb, Mo and Zn. This may reflect contribution of native elements in topsoil enrichment, especially in areas distant from the smelter.

Macrophytes drifting throughout the water column in the Detroit River were collected monthly from May to October 1985 to estimate the quantities of heavymetals being transported to Lake Erie by the plants. Most macrophytes (80–92% by weight) drifted at the water surface. Live submersed macrophytes made up the bulk of each sample. The most widely distributed submersed macrophyte in the river, American wildcelery (Vallisneria americana), occurred most frequently in the drift. A total of 151 tonnes (ash-free dry weight) of macrophytes drifted out of the Detroit River from May to October. The drift was greatest (37 tonnes) in May. Concentrations of heavymetals were significantly higher in macrophytes drifting in the river than in those growing elsewhere in unpolluted waters. Annually, a maximum of 2796 kg (eight heavymetals combined) were transported into Lake Erie by drifting macrophytes. The enrichment of all metals was remarkably high (range: 4000 × to 161000 ×) in macrophytes, relative to their concentration in water of the Detroit River. Detroit River macrophytes are thus a source of contaminated food for animals in the river and in Lake Erie.

"Phytoremediation" know-how to do-how is rapidly expanding and is being commercialized by harnessing the phyto-microbial diversity. This technology employs biodiversity to remove/contain pollutants from the air, soil and water. In recent years, there has been a considerable knowledge explosion in understanding plant-microbes-heavymetals interactions. Novel applications of plant-associated microbes have opened up promising areas of research in the field of phytoremediation technology. Various metabolites (e.g., 1-aminocyclopropane-1-carboxylic acid deaminase, indole-3-acetic acid, siderophores, organic acids, etc.) produced by plant-associated microbes (e.g., plant growth promoting bacteria, mycorrhizae) have been proposed to be involved in many biogeochemical processes operating in the rhizosphere. The salient functions include nutrient acquisition, cell elongation, metal detoxification and alleviation of biotic/abiotic stress in plants. Rhizosphere microbes accelerate metal mobility, or immobilization. Plants and associated microbes release inorganic and organic compounds possessing acidifying, chelating and/or reductive power. These functions are implicated to play an essential role in plant metal uptake. Overall the plant-associated beneficial microbes enhance the efficiency of phytoremediation process directly by altering the metal accumulation in plant tissues and indirectly by promoting the shoot and root biomass production. The present work aims to provide a comprehensive review of some of the promising processes mediated by plant-associated microbes and to illustrate how such processes influence heavymetal uptake through various biogeochemical processes including translocation, transformation, chelation, immobilization, solubilization, precipitation, volatilization and complexation of heavymetals ultimately facilitating phytoremediation. PMID:22580219

Investigations were carried out to isolate microbial strains from soil, mud and water samples from metallurgically polluted environment for bioremediation of toxic heavymetals. As a result of primary and secondary screening various 72 acidothermophilic autotrophic microbes were isolated and adapted for metal tolerance and biosorption potentiality. The multi-metal tolerance was developed with higher gradient of concentrations of Ag, As, Bi, Cd, Cr, Co, Cu, Hg, Li, Mo, Pb, Sn and Zn. The isolates were checked for their biosolubilization ability with copper containing metal sulfide ores. In case of chalcopyrite 85.82% and in covellite as high as 97.5% copper solubilization occurred in presence of 10(-3) M multi-heavymetals on fifth day at 55 degrees C and pH 2.5. Chemical analyses were carried out by inductively coupled plasma spectroscopy (ICP) for metal absorption. The selected highly potential isolate (ATh-14) showed maximum adsorption of Ag 73%, followed by Pb 35%, Zn 34%, As 19%, Ni 15% and Cr 9% in chalcopyrite. PMID:16324838

The Nador lagoon is a paralic system, located North-East of Morocco. At the present time this ecosystem undergoes an anthropic stress induced by urban, industrial and agricultural releases, and also by fishery activity which enriches this ecosystem in organic and inorganic wastes. A geochemical study has been undertaken, first to define the areas contaminated by heavymetals (Zn, Cu, Co, Cr and V), and second to caracterize the different mineral phases, which trap these elements. Sediment samples were collected on twenty-eight stations scattered all over the lagoon, and each core (30 cm) was subdivided in two horizons (surface and depth). Mineralogical analyses as well as major and trace elements analyses were performed on surface and deep sediments. The results on major element analyses (Si, Al, Ca, Mg, Na, P) show an enrichment in halite and phosphates in the surface sediments. This highlights on one hand, low water exchange rates between the lagoon and the Mediterranean sea, and on the other hand, an increase in organic releases related to the urban, agricultural and fishery activities. The highest concentrations in inorganic micro-pollutant were recorded N-E of the lagoon and close to Nador city. With reference to the geochemical background, it can be concluded that there is a slight contamination in heavymetals. Moreover, enrichment factor calculations (EF) for heavymetals point out an increase in metal elements as following: Zn>Co>Cr>V>Cu. Sequential extractions were performed to determine the behaviour of these micro-pollutants. Thus, it was shown that carbonates, oxides and phosphates are the preferential mineral phases for trapping these heavymetals.

Background We present herein our results regarding the accumulation of four heavymetals (copper, cadmium, lead, and zinc) in four aquatic species plants (Ceratophyllum demersum, Potamogeton pectinatus, Potamogeton lucens, Potamogeton perfoliatus) collected from the Danube River, South-Western part of Romania and their possible use as indicators of aquatic ecosystems pollution with heavymetals. Methods Elements concentration from the vegetal material was determined through Inductively Coupled Plasma – Mass Spectrometry. Results The species were chosen based on their previous use as bioindicators in aquatic ecosystems and due to the fact they are one of the most frequent aquatic plant species of the Danube River ecosystems within the Iron Gates Natural Park. Highest amounts are recorded for Ceratophyllum demersum (3.52 μg/g for Cd; 22.71 μg/g for Cu; 20.06 μg/g for Pb; 104.23 μg/g for Zn). Among the Potamogeton species, the highest amounts of heavymetals are recorded in Potamogeton perfoliatus (1.88 μg/g for Cd; 13.14 μg/g for Cu; 13.32 μg/g for Pb; 57.96 μg/g for Zn). The sequence for the bioconcentration factors (BCFs) calculated in order to describe the accumulation of the four metals is Cd >> Zn > Pb > Cu. Increase of the zinc concentration determines an increase of the cadmium concentration (Spearman rho=0.40, p=0.02). Conclusions Despite the low ambiental levels of heavymetals, the four aquatic plants have the ability to accumulate significant amounts, which make them useful as biological indicators. BCF value for Ceratophyllum demersum indicated this species as a cadmium hyperaccumulator. PMID:24359799

Two pulp and paper industrial wastes, lime mud (LM) and recovery boiler ash (RB), have low moisture contents, low heavymetal contaminations and contain various carbonate compounds which contribute to a high pH. Metal finishing wastewater (MF-WW) has a low pH, high levels of TDS and high contaminations from Cr, Cu, Pb and Zn. The heavymetals from MF-WW were removed by sorption and precipitation mechanisms. LM gave better results in removing heavymetals from MF-WW than RB. At a reaction time of 45min, the maximum removal efficiencies for Cr (93%) and Cu (99%) were obtained at 110gL(-1) of LM, but at 80gL(-1) for Pb (96%) and Zn (99%). Treatment with LM gives a higher sludge volume than with RB. However, the leachability of heavymetals from LM is lower. Leachability of heavymetals in the sediment for all selected treatment conditions is within government standards. PMID:19501952

Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavymetals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavymetals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavymetals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT]. PMID:20049231

The author describes work at PSI on thermohydraulics, thermal shock, and material tests for mechnical properties. In the presentation, the focus is on two main programs. (1) SINQ LBE target: The phase II study program for SINQ is planned. A new LBE loop is being constructed. The study has the following three objectives: (a) Pump study - design work on an electromagnetic pump to be integrated into the target. (b) Heat pipe performance test - the use of heat pipes as an additional component of the target cooling system is being considered, and it may be a way to futher decouple the liquid metal and water coolant loops. (c) Mixed convection experiment - in order to find an optimal configuration of the additional flow guide for window cooling, mixed convection around the window is to be studied. The experiment will be started using water and then with LBE. (2) ESS Mercury target: For ESS target study, the following experimental studies are planned, some of which are exampled by trial experiments. (a) Flow around the window: Flow mapping around the hemi-cylindrical window will be made for optimising the flow channels and structures, (b) Geometry optimisation for minimizing a recirculation zone behind the edge of the flow separator, (c) Flow induced vibration and buckling problem for a optimised structure of the flow separator and (d) Gas-liquid two-phase flow will be studied by starting to establish the new experimental method of measuring various kinds of two-phase flow characteristics.

Fly ash is an industrial waste generated from thermal power plants. Fly ash constitutes 80-85% of the total ash produced. A small part of fly ash is utilised in some sectors such as construction materials, building engineering, road, back fill, agriculture, selective engineering and processing useful materials. A large part of fly ash produced is disposed of with very high environmental risk. In the present paper, laboratory leaching test has been used to determine the potential mobility of Pb, Cd, Cr, Cu, Zn, Fe, Mn and Ni in fly ash samples, collected from Chandrapura Thermal Power Plant, Jharkhand and Ramagundam Super Thermal Power Plant, Andhra Pradesh, in order to assess their leachability when these wastes are disposed of. A cascade-leaching test was used at liquid-to-solid ratio (L/S) ranging between 20 and 100. Both fly ash samples exhibited neutral reactions, as indicated by pH values <11.75 and >7.0 at L/S=10 and contact time of 10 minutes. The percentage of leached amounts found to follow the trend Zn>Fe>Mn>Cr>Pb>Cu>Ni>Cd for fly ash from Chandrapura and Fe>Zn>Cu>Mn>Cr>Ni>Pb>Cd for fly ash from Ramagundam. Effect of pH on metals released from ash surface in aqueous solution followed a predictable pattern of decreasing release with increasing pH. PMID:19295096

Toxic compounds such as heavymetals exert chronic and lethal effects in animals, plants, and human health. With the rapid industrialization, urbanization, and economic development in Karachi, heavymetals are continuing to be introduced to estuarine and coastal environment through rivers, runoff and land-based point sources. Pollution in the Karachi coastal region (167 km long) is mainly attributed to Lyari and Malir Rivers flowing through the city of Karachi. Both rivers are served by various channels of domestic and industrial wastes carrying more than 300 million gallons per day untreated effluent of 6000 industries and ultimately drain into the beaches of Arabian Sea. Concentrations of selected heavymetals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surface sediments from eighty-eight sites in Karachi coastal region were studied in order to understand metal contamination due to industrialization, urbanization, and economic development in Karachi. Sediment samples were collected in 2005 and 2006. We have found that heavymetal concentrations in surface sediments varied from 0.006 to 24.3 ug/g for Cd, 5.1 to 95 ug/g for Co, 2.9 to 571 ug/g for Cr, 6.9 to 272 ug/g for Cu, 0.55 to 6.5% for Fe, 1.2 to 318 ug/g for Mn, 7.5 to 75 ug/g for Ni, 6.3 to 121 ug/g for Pb, and 3.3 to 389 ug/g for Zn. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The highest levels of metals were found to be at the confluence of the Lyari and Malir River streams at the Arabian Sea, indicating the impact of the effluents of the highly urbanized and industrialized city of Karachi. Furthermore, this study assessed heavymetal toxicity risk with the application of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM). Results indicated that the potential toxicity of marine environment can cause adverse biological effects to the biota directly and the human health

With decreasing availability of phosphorus from primary resources its recovery from waste streams becomes increasingly more important. Sewage sludge ash is rich in phosphorus, but the direct use as fertilizer is limited because of inorganic contaminants such as heavymetals and strong bonding of phosphorous in the ash. Electrodialysis (ED) can be used to recover phosphorus and simultaneously remove heavymetals. The present work is an experimental screening of different options for ED in relation to experimental setup and combination with acid addition. Experiments for stirred ash suspensions utilizing a three compartment cell setup where the anode, cathode and stirred suspension are separated by ion exchange membranes are reported. Simplifying this experimental setup by removing the anion exchange membrane brings the anode in direct contact with the stirred ash suspension. Through this adjustment, half-reactions at the anode contribute to the acidity of the stirred suspension resulting in increased dissolution of both phosphorus and heavymetals (Cd, Cu, Cr, Pb, Zn, Ni) and better separation of most heavymetals from the stirred ash suspension. When the ash is suspended in an acidic solution, these effects increase significantly in early stages of the experiments. The combination of ED in a two compartment setup and initial acidification of the stirred suspension is most effective in dissolving of phosphorus and separation of heavymetals. In this setup, up to 96% of the phosphorus in the ash was dissolved after 7 d. Using the three compartment setup and initially suspending the ash in distilled water, resulted in 53% dissolution of the total recovered phosphorus after 7 d. PMID:25548038

Compositions of heavymetals including Cu, Zn, Cr and Pb in three sediment cores recovered from the lower basin of the Changjiang (Yangtze River) and the inner shelf mud of the East China Sea were analyzed by traditional X-ray florescence (XRF) and XRF Core Scanner. This study aims to investigate the accumulation of heavymetals in the fluvial sediments and to decipher the influence of anthropogenic activities within the large catchment over the last 150 years. The data suggest that the heavymetals, especially Pb and Zn, show obvious enrichments in concentrations since 1950s, and the small and consistent variations of heavymetal concentrations before 1950s can represent geochemical background values. After removing the grain size effect on elemental concentrations, we infer that the sources of heavymetals predominantly come from natural weathering detritus, while human contamination has increased over the last half century. The calculations of both enrichment factor and geoaccumulation index, however, indicate that the pollution of these heavymetals in the fluvial and shelf environments is not significant. The rapid increase in human activities and fast socioeconomic development in the Changjiang catchment and East China over the last five decades accounts for the enrichments of heavymetals in the river and marine sediments. The inner shelf of the East China Sea, as the major sink of the Changjiang-derived fine sediments, provides a high-resolution sediment archive for tracing the anthropogenic impacts on the catchment. PMID:26580732

Mining-affected lands are a global issue; in the USA alone there are an estimated 500,000 abandoned mines encompassing hundreds of thousands of hectares. Many of these sites generate acidic mine drainage that causes release of heavymetals, and subsequently degradation in environmental quality. Because of its potential liming characteristics, biochar may play a pivotal role as a soil amendment in future mine land reclamation. However, to date, most studies have focused on the use of biochar to sorb metals from solution. Previous studies suggest that metals are complexed by biochar surface function groups (leading to ion exchange, complexation), coordination with Pi electrons (C=C) of carbon, and precipitation of inorganic mineral phases. Several recent studies have focused on the use of biochar for amending mine land soils, showing that biochar can indeed reduce heavymetal lability, yet the mechanism(s) behind labile metal reduction have yet to be established. In a proof-of-concept study, we added lodgepole pine, tamarisk, and switchgrass biochar (0, 5, 10, 15% by weight; 500 oC) to four different western US mine land soils affected by various heavymetals (Cd, Cu, Mn, Pb, Zn). Extraction with 0.01M CaCl2 showed that increasing biochar application rate significantly decreased 'bioaccessible' metals in almost all instances. A concomitant increase in solution pH was observed, suggesting that metals may be rendered bio-inaccessible through precipitation as carbonate or (hydr)oxide phases, or sorbed onto mineral surfaces. However, this was only supposition and required further research. Thus, following the 0.01M CaCl2 extraction, biochar-soil mixtures were air-dried and metals were further extracted using the four-step BCR sequential removal procedure. Results from selective extraction suggest that, as compared to the controls, most metals in the biochar-amended mine land soils were associated with exchange sites, carbonate, and oxide phases. Biochar may play a

Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavymetals. Microorganisms including fungi have been reported to exclude heavymetals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavymetals for higher tolerance and removal of heavymetals from wastewater. Seventy-six fungal isolates tolerant to heavymetals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavymetals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavymetal tolerant fungi were studied for removal of heavymetals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavymetals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavymetals from wastewater and industrial effluents containing higher concentration of heavymetals. PMID:23024411

Heavymetals produced and released during agricultural and industrial activities may pose a serious threat to the environment. This study investigated the effectiveness of phosphatic clay, a by-product of the phosphate mining industry, for immobilizing heavymetals (Pb(+2), Cd(+2), and Zn(+2)) from aqueous solutions. A batch equilibrium technique was adopted to evaluate metal sorption in the presence of 0.05 M KNO3 background electrolyte solution. The amounts of metals sorbed onto phosphatic clay decreased in the order Pb(+2) > Cd(+2) > Zn(+2). Desorption data suggest that a large fraction of metals sorbed onto phosphatic clay stayed intact under a wide variation in extracting solution pH (ranging from 3 to 10). Desorption rates were slowest for Pb followed by Cd and Zn. Only 8.1 to 23.1% of Pb, 8.4 to 45% of Cd, and 21.9 to 73.9% of Zn sorbed on phosphatic clay was mobilized by USEPA toxicity characteristic leaching procedure (TCLP) solutions at pH 2.93+/-0.05 and 4.93+/-0.05, respectively. Formation of fluoropyromorphite [Pb10(PO4)6(F2)], confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), after reaction of aqueous Pb with phosphatic clay suggested that precipitation remained the dominant mechanism for Pb removal from aqueous solution. In the case of aqueous Cd and Zn interaction with phosphatic clay, we are not able to confirm the formation of a new amorphous and/or crystalline phase on the basis of available information. Other possible sorption mechanisms for Cd and Zn may include sorption and coprecipitation. Thus, phosphatic clay may be an effective amendment for in situ immobilization of heavymetals in contaminated soils and sediments. PMID:11790002

Incineration of wastes, widely and increasingly used nowadays, produces residues, mainly bottom ash and filter fly ash. Fly ash is especially problematic because of its high content in heavymetals easily drawn out. Thermal processes, based mainly on electrical arc processes, are used to melt the residues at high temperature and convert them into a relatively inert glass. Consequently, to improve the process and get a glass satisfying regulation, control of heavymetals (lead, zinc, cadmium and chromium...) volatility during plasma fly ash melting and vitrification is needed and basic data concerning vaporization of these metals are required. According to the volatility of these compounds observed during vitrification of fly ash, a predictive model has been used to simulate the elimination of Pb, Zn and S from the melt as a function of time and temperature for a system including chlorides, oxides and sulfates. The objective of this work was the experimental study of heavymetals volatility using optical emission spectroscopy. A twin torch plasma system, mounted above a cold crucible with Ar (or Ar + O2) as plasma gas, has been used. The crucible was filled with synthetic glass in which known amounts of metallic salts were added to obtain the same chemical composition as used in the model. From spectral lines intensities of Ar, the plasma temperature profiles along the observation direction has been first established, before using ratios of spectral lines of Ar and metallic (Pb, Zn) or Cl vapors to reach the evolution of the elements concentrations above the melt. Off-gases have been analyzed by mass spectrometry. The influence of the atmosphere (Ar or Ar + O2) above the crucible has been studied and differences in elements behaviors have been pointed out. The results of the spectroscopic measurements have been compared to the ones issued of modeling, in order to validate our model of vaporization.

Incineration of wastes, widely and increasingly used nowadays, produces residues, mainly bottom ash and filter fly ash. Fly ash is especially problematic because of its high content in heavymetals easily drawn out. Thermal processes, based mainly on electrical arc processes, are used to melt the residues at high temperature and convert them into a relatively inert glass. Consequently, to improve the process and get a glass satisfying regulation, control of heavymetals (lead, zinc, cadmium and chromium…) volatility during plasma fly ash melting and vitrification is needed and basic data concerning vaporization of these metals are required. According to the volatility of these compounds observed during vitrification of fly ash, a predictive model has been used to simulate the elimination of Pb, Zn and S from the melt as a function of time and temperature for a system including chlorides, oxides and sulfates. The objective of this work was the experimental study of heavymetals volatility using optical emission spectroscopy. A twin torch plasma system, mounted above a cold crucible with Ar (or Ar + O2) as plasma gas, has been used. The crucible was filled with synthetic glass in which known amounts of metallic salts were added to obtain the same chemical composition as used in the model. From spectral lines intensities of Ar, the plasma temperature profiles along the observation direction has been first established, before using ratios of spectral lines of Ar and metallic (Pb, Zn) or Cl vapors to reach the evolution of the elements concentrations above the melt. Off-gases have been analyzed by mass spectrometry. The influence of the atmosphere (Ar or Ar + O2) above the crucible has been studied and differences in elements behaviors have been pointed out. The results of the spectroscopic measurements have been compared to the ones issued of modeling, in order to validate our model of vaporization.

Growth and heavy-metal uptake of various food crops and grass cultivated on harbour dredge spoils were studied, and health aspects in consuming the marketable products were discussed. Vegetables (potato, carrot, radish, endive, lettuce) and grass (English ryegrass) performed well on dredge spoils, but small grains (wheat, barley) were affected by manganese deficiency. As compared with crops grown on uncontaminated reference soils, there was a net accumulation of As and heavymetals, especially so Cd, Zn and Cu, and a reduced uptake of Mn. Mainly because of the elevated Cd concentrations of the edible parts, exceeding the guideline of 0.1 mg/kg in fresh matter, the harbour dredge spoils investigated are considered unfit for the production of food crops, but may be used as grassland for dairy cattle. Highest Cd concentrations were attained in leafy vegetables and wheat (grain) and lowest in potato (tuber). PMID:7156971

High concentrations of heavymetals (HM) in the soil have detrimental effects on ecosystems and are a risk to human health as they can enter the food chain via agricultural products or contaminated drinking water. Phytoremediation, a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants, is becoming an increasingly important objective in plant research. However, as phytoremediation is a slow process, improvement of efficiency and thus increased stabilization or removal of HMs from soils is an important goal. Arbuscular mycorrhizal (AM) fungi provide an attractive system to advance plant-based environmental clean-up. During symbiotic interaction the hyphal network functionally extends the root system of their hosts. Thus, plants in symbiosis with AM fungi have the potential to take up HM from an enlarged soil volume. In this review, we summarize current knowledge about the contribution of the AM symbiosis to phytoremediation of heavymetals. PMID:16555102

Effect of sublethal heavymetal stress as plant biotic elicitor for triggering innate immunity in tomato plant was investigated. Copper in in vivo condition induced accumulation of defense enzymes like peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), and β-1,3 glucanase along with higher accumulation of total phenol, antioxidative enzymes (catalase and ascorbate peroxidase), and total chlorophyll content. Furthermore, the treatment also induced nitric oxide (NO) production which was confirmed by realtime visualization of NO burst using a fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2DA) and spectrophotometric analysis. The result suggested that the sublethal dose of heavymetal can induce an array of plant defense responses that lead to the improvement of innate immunity in plants. PMID:25729768

Methods for in situ formation in soil of a permeable reactive barrier or zone comprising a phosphate precipitate, such as apatite or hydroxyapatite, which is capable of selectively trapping and removing radionuclides and heavymetal contaminants from the soil, while allowing water or other compounds to pass through. A preparation of a phosphate reagent and a chelated calcium reagent is mixed aboveground and injected into the soil. Subsequently, the chelated calcium reagent biodegrades and slowly releases free calcium. The free calcium reacts with the phosphate reagent to form a phosphate precipitate. Under the proper chemical conditions, apatite or hydroxyapatite can form. Radionuclide and heavymetal contaminants, including lead, strontium, lanthanides, and uranium are then selectively sequestered by sorbing them onto the phosphate precipitate. A reducing agent can be added for reduction and selective sequestration of technetium or selenium contaminants.

Bladder cancer takes the second place in the classification of morbidity of urinary system cancers. Many chemical factors take part in cancerogenesis. It is suggested that exposure to heavymetals such as arsenic, chromium, nickel and cadmium as well as its metabolites may trigger the bladder cancer through inducing excessive reactive oxygen species production and oxidative stress formation which are responsible for DNA damage. In patients with bladder cancer is observed the disorder of processes regulated by p-53, including apoptosis. There are many patients with bladder cancer with confirmed absence of retinoblastoma protein, which is responsible of holding on the process of coming up the cells with mutation into synthesis, where the replication process undergoes. It is mentioned that excessive expression of proto-oncogenes may also cause the bladder cancer. The article concerns biochemical effects of exposure to chosen heavymetals and their potential role in bladder cancer progression. PMID:26689010

The study was navigated to examine the metal biosorbing ability of bacterial strain OSM29 recovered from rhizosphere of cauliflower grown in soil irrigated consistently with industrial effluents. The metal tolerant bacterial strain OSM29 was identified as Bacillus thuringiensis following 16S rRNA gene sequence analysis. In the presence of the varying concentrations (25–150 mgl−1) of heavymetals, such as cadmium, chromium, copper, lead and nickel, the B. thuringiensis strain OSM29 showed an obvious metal removing potential. The effect of certain physico-chemical factors such as pH, initial metal concentration, and contact time on biosorption was also assessed. The optimum pH for nickel and chromium removal was 7, while for cadmium, copper and lead, it was 6. The optimal contact time was 30 min. for each metal at 32 ± 2 °C by strain OSM29. The biosorption capacity of the strain OSM29 for the metallic ions was highest for Ni (94%) which was followed by Cu (91.8%), while the lowest sorption by bacterial biomass was recorded for Cd (87%) at 25 mgl−1 initial metal ion concentration. The regression coefficients obtained for heavymetals from the Freundlich and Langmuir models were significant. The surface chemical functional groups of B. thuringiensis biomass identified by Fourier transform infrared (FTIR) were amino, carboxyl, hydroxyl, and carbonyl groups, which may be involved in the biosorption of heavymetals. The biosorption ability of B. thuringiensis OSM29 varied with metals and was pH and metal concentration dependent. The biosorption of each metal was fairly rapid which could be an advantage for large scale treatment of contaminated sites. PMID:24115905

Total mass transfers of heavymetal in dissolved and particulate form has been determined in the downstream section of river Hindon, an important tributary of river Yamuna (India). The contribution of different point sources to the river Hindon has also been assessed. The river Kali has the largest contribution to the river Hindon. The highest metal loads were related to the highest flow of the river and thereby increased both by surface runoff and sediment resuspension. The contribution of monsoon months to the total transported load was also calculated and it was observed that monsoon months contributes more than 40% of total loading annually for all the metals. The metal fluxes from the river Hindon were compared with other rivers of Indian sub-continent. PMID:16404544

In this study metal accumulating abilities of three emergent macrophytes (Phragmites australis, Typha capensis and Spartina maritima) were investigated in the urbanised Swartkops Estuary. Plants and sediment samples were collected at seven sites along the banks of the main channel and in adjacent canals. Sediments and plant organs were analysed, by means of atomic absorption spectrometry, for four elements (Cd, Cu, Pb, and Zn). Metal concentrations in the sediments of adjacent canals were found to be substantially higher than those at sites along the banks of the estuary. These differences were reflected in the plant organs for Pb and Zn, but not for Cu and Cd. All three species exhibited significantly higher concentrations of metals in their roots. These species are therefore suitable for use as indicators of the presence and level of heavymetal contaminants in estuaries. PMID:25599629

The effects of gravity on the crystal nucleation of heavymetal fluoride fibers have been studied in preliminary experiments utilizing NASA's KC-135 reduced gravity aircraft and a microgravity sounding rocket flight. Commercially produced fibers were heated to the crystallization temperature in normal and reduced gravity. The fibers processed in normal gravity showed complete crystallization while the fibers processed in reduced gravity did not show signs of crystallization.

Abstract Background The aim of the present study was to evaluate the capability of helminths to absorb heavymetals in comparison with that of the host tissues. Methods We compared the concentration of cadmium (Cd) and chromium (Cr) in urban rats and in their harboring helminthes —Moniliformis moniliformis, Hymenolepis diminuta and larval stage of Taenia taenaeiformis (Cysticercus fasciolaris). The heavymetal absorption was evaluated in 1g wet weight of parasites and tissues digested in nitric acid, using Inductivity Coupled Plasma (ICP_OES). Results A higher concentration of heavymetals was revealed in the helminths than in the host tissues. Bioconcentration factor (BF= C in parasite/C in tissue) for both Cd and Cr absorption was more than 10-fold higher in M. moniliformis than in the three compared host tissues. The BF of Cd in M. moniliformis compared to the liver, kidney and muscle of the host was 9.16, 14.14 and 17.09, respectively. BF in Cr in the same parasite and the same host tissues ranged from 10.67, 7.06 and 4.6. High level of absorption in H. diminuta was significantly likewise; the individual BF of Cd and Cr in H. diminuta compared to the liver, kidney and muscle of the hosts was 4.95, 5.94 and 4.67 vs. 2.67, 11.56 and 5.59. The mean concentration of Cd and Cr in C. fasciolaris was also significantly higher than that in the rat livers (P<0.007 and P<0.004, respectively). Conclusion This study claims that parasites of terrestrial animals exposed to heavymetals can be more accurate indicators than the host tissues as new environmental monitoring agents. PMID:25988090

Background: Contamination of vegetable crops (as an important part of people's diet) with heavymetals is a health concern. Therefore, monitoring levels of heavymetals in vegetables can provide useful information for promoting food safety. The present study was carried out in north-west of Iran (Tabriz) on the content of heavymetals in vegetable crops. Methods: Samples of vegetables including kurrat (n=20) (Allium ampeloprasumssp. Persicum), onion (n=20) (Allium cepa) and tomato (n=18) (Lycopersiconesculentum var. esculentum), were collected from production sites in west of Tabriz and analyzed for presence of Cd, Cr, Cu, Ni, Pb and Zn by atomic absorption spectroscopy (AAS) after extraction by aqua regia method (drying, grounding and acid diges­tion). Results: Mean ± SD (mg/kg DW) concentrations of Cd, Cu, Cr, Ni and Zn were 0.32 ± 0.58, 28.86 ± 28.79, 1.75 ± 2.05, 6.37± 5.61 and 58.01 ± 27.45, respec­tively. Cr, Cu and Zn were present in all the samples and the highest concentra­tions were observed in kurrat (leek). Levels of Cd, Cr and Cu were higher than the acceptable limits. There was significant difference in levels of Cr (P<0.05) and Zn (P<0.001) among the studied vegetables. Positive correlation was observed be­tween Cd:Cu (R=0.659, P<0.001) Cr:Ni (R=0.326, P<0.05) and Cr:Zn (R=0.308, P<0.05). Conclusion: Level of heavymetals in some of the analyzed vegetables, especially kurrat samples, was higher than the standard levels. Considering the possi­ble health outcomes due to the consumption of contaminated vegetables, it is re­quired to take proper actions for avoiding people's chronic exposure. PMID:24688968

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavymetal ions for removal from a soil or aquatic environment.

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavymetal ions for removal from a soil or aquatic environment.

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavymetal ions for removal from a soil or aquatic environment.

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavymetal ions for removal from a soil or aquatic environment.

In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavymetals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavymetal ions, and the immobilization efficiency reach 98.5% greater when heavymetals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavymetals. PMID:17034943

Self-assembly regulated by hydrogen bonds was successfully achieved in the system of lithocholic acid (LCA) mixed with three organic amines, ethanolamine (EA), diethanolamine (DEA), and triethanolamine (TEA), in aqueous solutions. The mixtures of DEA/LCA exhibit supergelation capability and the hydrogels consist of plenty of network nanotubes with uniform diameters of about 60 nm determined by cryogenic TEM. Interestingly, the sample with the same concentration in a system of EA and LCA is a birefringent solution, in which spherical vesicles and can be transformed into nanotubes as the amount of LCA increases. The formation of hydrogels could be driven by the delicate balance of diverse noncovalent interactions, including electrostatic interactions, hydrophobic interactions, steric effects, van der Waals forces, and mainly hydrogen bonds. The mechanism of self-assembly from spherical bilayer vesicles into nanotubes was proposed. The dried hydrogels with nanotubes were explored to exhibit the excellent capability for capturing heavy-metal ions, for example, Cu(2+), Co(2+), Ni(2+), Pb(2+), and Hg(2+). The superhydrogels of nanotubes from the self-assembly of low-molecular-weight gelators mainly regulated by hydrogen bonds used for the removal of heavy-metal ions is simple, green, and high efficiency, and provide a strategic approach to removing heavy-metal ions from industrial sewage. PMID:24136830

Summary Aims The aim of this research is to verify the quality and quantity of heavymetals (HM) of dental origin in TMD patients. Methods A population of 100 subject was studied and divided in two homogeneous groups: Study Group (SG) and Control Group (CG). Organism heavymetals were tested by a spot sampling method in which the first urine of the day, through Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), were analyzed. The results obtained were compared with reference values (RV) of Italian people. Descriptive statistical analysis and student’s t-test has been applied (statistical significance for p > 0.05). Results The SG presented the absolute highest levels of HM compared to the CG (p=0.787). As regards the relation between pain and HM, the subjects that refer “severe/very severe” values of pain present the highest levels of HM in urines. Conclusions The obtained results seem to highlight a possible direct proportionality between the level of pain the increase of the concentration of heavymetals in all the examined groups and subgroups. PMID:25002917

Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavymetals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavymetal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called “Anthropocene”. According to its heavymetal concentration, these sediments meet the present-day standards of “contaminated soil”. Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence. PMID:26388184

For consumption of health foods of Spirulina, by the general public, health food stores are increasingly offering more exotic products. Though Spirulina consumption is growing worldwide, relatively few studies have reported on the quantities of heavymetals/minerals they contain and/or their potential effects on the population’s health. This study reveals the concentrations of six typical heavymetals/minerals (Ni, Zn, Hg, Pt, Mg, and Mn) in 25 Spirulina products commercialized worldwide for direct human consumption. Samples were ground, digested and quantified by Coupled Plasma Mass Spectroscopy (ICP–MS). The concentrations (mg/kg d.w.) were range from 0.001 to 0.012 (Pt) followed by 0.002–0.028 (Hg), 0.002–0.042 (Mg), 0.005–2.248 (Mn), 0.211–4.672 (Ni) and 0.533–6.225 (Zn). The inorganic elements of the present study were significantly lower than the recommended daily intake (RDI) level of heavymetal elements (mg/daily) Ni (0.4), Zn (13), Hg (0.01), Pt (0.002), Mg (400) and Mn (4). Based on this study the concentration of inorganic elements was not found to exceed the present regulation levels, and they can be considered as safe food. PMID:24235875

The Taimyr Peninsula is directly north of the world's largest heavymetal smelting complex (Norilsk, Russia). Despite this proximity, there has been little research to examine the extent of contamination of the Taimyr Peninsula. We analyzed heavymetal concentrations in lichen (Cetraria cucullata), moss (Hylocomium splendens), soils, lake sediment, freshwater fish (Salvelinus alpinus, Lota lota, and Coregonus spp.) and collared lemming (Dicrostonyx torquatus) from 13 sites between 30 and 300 km from Norilsk. Element concentrations were low in both C. cucullata and H. splendens, although concentrations of Al, Fe, Cu, Ni, and Pb were significantly higher than those in Arctic Alaska, probably due to natural differences in the geochemical environments. Inorganic surface soils had significantly higher concentrations of Cd, Zn, Pb, and Mg than inorganic soils at depth, although a lake sediment core from the eastern Taimyr Peninsula indicated no recent enrichment by atmospherically transported elements. Tissue concentrations of heavymetals in fish and lemming were not elevated relative to other Arctic sites. Our results show that the impact of the Norilsk smelting complex is primarily localized rather than regional, and does not extend northward beyond 100 km.

Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavymetals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavymetal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called “Anthropocene”. According to its heavymetal concentration, these sediments meet the present-day standards of “contaminated soil”. Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence.

Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavymetals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavymetal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called "Anthropocene". According to its heavymetal concentration, these sediments meet the present-day standards of "contaminated soil". Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence. PMID:26388184

In this investigation polarographic methods (along with GFAAS and ICP) have been used to study the distribution of lead and chromium in Bayou Trepagnier and Devil`s Swamp. Both laboratory and field research have been conducted. Separation and extraction methodology appropriate for analysis of the contaminants at these sites have been developed. Particular attention has been paid to extraction methods for chromium which do not lead to valence state conversion. The availability of such techniques is essential to take full advantage of polarography, a method capable of performing speciation analysis. The results indicate that there is a very inhomogeneous distribution of heavymetals in these environments. In Devil`s Swamp, for example, separation and analysis of aqueous and variously sized particulate moieties in the water and sediment compartments were conducted to determine the partition of lead between them. The results showed that the average lead content was 14.7 ppb and 19.8 ppm, respectively, in these compartments. Apparently bull frogs in Devil`s Swamp can bioaccumulate lead (compared to the measured water level), since the muscle concentration was found to be about 0.6 ppm. This phenomenon is being investigated in a Xenopus frog laboratory model of heavymetal uptake. The basic methodology validated in this study should be fairly generally applicable to assays of other heavymetals.

Smart responsive microcapsules capable of recognizing heavymetal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavymetal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavymetal ions. PMID:20656104

Background: The main objective of this study was characterization of selected heavymetals concentrations (Lead, cadmium, copper, zinc, nickel and chromium) in groundwater used for ir-rigation in Tabriz City's countryside. Methods: After consulting with the experts of agriculture department and site survey, 38 irriga-tion water samples were taken from different farms (34 wells) without primary coordination with farm owners. All of samples were acidified to achieve pH≈2 and then were concentrated from 10 to 1 volume. The concentrations of Cd, Pb, Cu, Cr, Ni, and Zn in the samples (totally 228) were determined with a flame atomic absorption spectrophotometer. Results: In none of 38 farms, irrigation with surface runoff and industrial wastewater was ob-served. The average concentrations of Cd, Pb, Cu, Cr, Ni, and Zn in the irrigated water were de¬termined 6.55, 0.79, 16.23, 3.41, 4.49, and 49.33µg/L, respectively. The average and even maxi¬mum concentrations of heavymetals in the irrigation water at the studied area were less than toxicity threshold limits of agricultural water. Conclusion: Currently, not using of surface runoff and industrial wastewater as irrigation water by farmers indicates that the controlling efforts by authorities have been effective in the area. Water used for irrigation of the farms and groundwater of the studied area are not polluted with heavymetals and there is no risk from this viewpoint in the region. PMID:24688935

The availability of high quality optical fibers with transmission window, larger than that of silica fiber, extends the use of optical fibers and open new application fields. There is increasing demand of optical fiber with transmission over 2 microns, where silica is opaque, for applications as diverse as sensing, fiber lasers and amplifiers, defense (IRCM), spectroscopy... No materials can fulfill all applications needs. Engineers have to make some compromise when choosing the right materials for the right application. Heavymetal fluoride glass is one of these materials. The glass, under bulk form, has a wide transmission window from 0.3 up to 8 microns, without any absorption peaks. Heavymetal fluoride glass fibers are drawn using the preform technique, the same technique used for silica fiber. This technique has proven to allow good control of fiber dimensions and geometry. Fluoride glass fibers with different exotics shapes have already been obtained, such as D-shaped, square, of centered fiber, multi cladding fibers and microstructured fibers.... As far as active fibers are concerned, heavymetal fluoride glasses have low phonon energy and can contain high concentration of active ions, rare-earth elements. Therefore, new laser lines have been already demonstrated using fluoride glass fibers. Fiber lasers with output power exceeding 10 w have been obtained by different groups. This paper will present the latest development of fluoride glass fiber technology, including fibers optical and mechanical properties, fiber lasers and power handling.

Levels of contaminants in fish are of particular interest because of the potential risk to humans who consume them. While attention has focused on self-caught fish, most of the fish eaten by the American public comes from commercial sources. We sampled 11 types of fish and shellfish obtained from supermarkets and specialty fish markets in New Jersey and analyzed them for arsenic, cadmium, chromium, lead, manganese, mercury, and selenium. We test the null hypothesis that metal levels do not vary among fish types, and we consider whether the levels of any metals could harm the fish themselves or their predators or pose a health risk for human consumers. There were significant interspecific differences for all metals, and no fish types had the highest levels of more than two metals. There were few significant correlations (Kendall tau) among metals for the three most numerous fish (yellowfin tuna, bluefish, and flounder), the correlations were generally low (below 0.40), and many correlations were negative. Only manganese and lead positively were correlated for tuna, bluefish, and flounder. The levels of most metals were below those known to cause adverse effects in the fish themselves. However, the levels of arsenic, lead, mercury, and selenium in some fish were in the range known to cause some sublethal effects in sensitive predatory birds and mammals and in some fish exceeded health-based standards. The greatest risk from different metals resided in different fish; the species of fish with the highest levels of a given metal sometimes exceeded the human health guidance or standards for that metal. Thus, the risk information given to the public (mainly about mercury) does not present a complete picture. The potential of harm from other metals suggests that people not only should eat smaller quantities of fish known to accumulate mercury but also should eat a diversity of fish to avoid consuming unhealthy quantities of other heavymetals. However, consumers should

This study investigated the removal of heavymetal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavymetal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavymetal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

The design of stormwater wetlands and ponds as wildlife habitats has prompted concern over the potential uptake of runoff contaminants by aquatic fauna. Stormwater wetlands provide a diverse array of habitat for aquatic macroinvertebrates. The importance of macroinvertebrates in aquatic communities has been well documented. Aquatic macroinvertebrates also serve as a major food source of many aquatic vertebrates, including fish and birds. The objectives of the study were to: (1) examine the responses of the macroinvertebrate community to water and sediment concentrations of heavymetals, and other water quality parameters; (2) determine whether macroinvertebrates living in stormwater wetlands bioaccumulate significant concentrations of heavymetals; (3) relate the concentrations of heavymetals in sediment, water and macroinvertebrates to land use in the surrounding watershed; (4) determine sediment and water toxicity to macroinvertebrates. Twenty stormwater wetlands, representing four land uses commercial, residential, highway and control, were monitored in this study. Water quality parameters, including pH, DO, turbidity, conductivity, hardness and metal concentrations were monitored bi-weekly for six months. Sediment samples were collected three times during the same period. Macroinvertebrate communities were sampled during alternate weeks after water collections. Ten-day sediment bioassays were conducted using the amphipod Hyalella azteca. Preliminary data analyses have indicated no significant difference in sediment and water metal concentrations between land uses. However, Zn concentrations in macroinvertebrates were significantly higher (p < 0.05) in wetlands serving commercial watersheds than in those serving the remaining three land uses. No differences have been detected in composition of invertebrate communities due to land use category.

Phytoextraction is an environmentally sound method for cleaning up sites that are contaminated with toxic heavymetals. However, the method has been questioned because it produces a biomass-rich secondary waste containing the extracted metals. Therefore, further treatment of this biomass is necessary. In this study, we investigated whether thermal treatment could be a feasible option for evaporatively separating metals from the plant residues. We used a laboratory scale reactor designed to simulate the volatilization behavior of heavymetals in a grate furnace. The evaporation of alkali and heavymetals from plant samples was investigated online, using a thermo-desorption spectrometer (TDS). Experiments were performed in the temperature range of 25-950 degrees C with leaves of the Cd and Zn hyperaccumulator Thlaspi caerulescens and of the high biomass plant Salix viminalis (willow), both grown on contaminated soils. Gasification (i.e., pyrolysis), which occurs under reducing conditions, was a better method than incineration under oxidizing conditions to increase volatilization and, hence subsequently recovery, of Cd and Zn from plants. It would also allow the recycling of the bottom ash as fertilizer. Thus, our investigations confirmed that incineration (or co-incineration) is a viable option for the treatment of the heavymetal-enriched plants. PMID:15926590

Conventional physicochemical technologies to remediate heavymetals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavymetals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavymetals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavymetals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavymetals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc) and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials. PMID:26236176

The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavymetals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc) and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials. PMID:26236176

Heavymetals are pollutants which affect all organisms. Since a small number of eukaryotes have been investigated with respect to metal resistance, we hypothesize that many genes that control this phenomenon remain to be identified. This was tested by screening soil eukaryotic metatranscriptomes which encompass RNA from organisms belonging to the main eukaryotic phyla. Soil-extracted polyadenylated mRNAs were converted into cDNAs and 35 of them were selected for their ability to rescue the metal (Cd or Zn) sensitive phenotype of yeast mutants. Few of the genes belonged to families known to confer metal resistance when overexpressed in yeast. Several of them were homologous to genes that had not been studied in the context of metal resistance. For instance, the BOLA ones, which conferred cross metal (Zn, Co, Cd, Mn) resistance may act by interfering with Fe homeostasis. Other genes, such as those encoding 110- to 130-amino-acid-long, cysteine-rich polypeptides, had no homologues in databases. This study confirms that functional metatranscriptomics represents a powerful approach to address basic biological processes in eukaryotes. The selected genes can be used to probe new pathways involved in metal homeostasis and to manipulate the resistance level of selected organisms. PMID:23663419

Soil contamination by heavymetal and, though it, of groundwater represent a serious alteration of original geochemical levels owing to various human activities as: particular industrial processes and their non-correct treatment emission, urban traffic, use of phytosanitary product and mineral fertilizer. Heavymetals are genotoxic contaminants who can be found by environmental matrix analysis or by examination of the genetic damage inducted, after exposition, to sentry organism. In this last case we use a relative quantitation of the gene expression monitoring the mitochondrial oxidative metabolism hepatopancreas's gene of the organism used by bioindicator. This test is based on consideration that the hepatopancreas is the first internal organ affected by heavymetals or any other pollutant that the organism is exposed. In this work, the organism used by bioindicator to evalutate the pollutant contamination of waste water is Danio rerio (Zebrafish) that is a little tropical fish of 2-3 cm, native on asiatic south-east rivers. This organism has a large use in scientific field because its genoma is almost completely mapped and, above all, because the congenital gene cause in human, if it was mutated in zebrafish, similar damage or almost similar mutation that happens in human being so you can develop a dose - response curve. To do this, after prepared a cadmium solution with a concentration 10 times the Italian normative limit, the organisms have been put in the aquarium to recreate the optimal condition to survival of zebrafish observed by continuous monitoring by web-cam. After one month exposition, that we took little by little sample fish to analyzing, for different exposition time, the hepatopancreas's fish. First results shows considerable variation of the gene expression by interested gene in mitochondrial oxidative metabolism compared to control, highlighting the mutagenity caused by heavymetals on Danio rerio's hepatopancreas and, mutatis mutandis, also in

Whole-cell bacterial bioreporters represent a convenient testing method for quantifying the bioavailability of contaminants in environmental samples. Despite the fact that several bioreporters have been constructed for measuring heavymetals, their application to environmental samples has remained minimal. The major drawbacks of the available bioreporters include a lack of sensitivity and specificity. Here, we report an improvement in the limit of detection of bacterial bioreporters by interfering with the natural metal homeostasis system of the host bacterium. The limit of detection of a Pseudomonas putida KT2440-based Zn/Cd/Pb-biosensor was improved by a factor of up to 45 by disrupting four main efflux transporters for Zn/Cd/Pb and thereby causing the metals to accumulate in the cell. The specificity of the bioreporter could be modified by changing the sensor element. A Zn-specific bioreporter was achieved by using the promoter of the cadA1 gene from P. putida as a sensor element. The constructed transporter-deficient P. putida reporter strain detected Zn(2+) concentrations about 50 times lower than that possible with other available Zn-bioreporters. The achieved detection limits were significantly below the permitted limit values for Zn and Pb in water and in soil, allowing for reliable detection of heavymetals in the environment. PMID:21326938

During the growing season, comparisons wer made of the leaf surface microflora of (i) two groups of mature oak trees, one in the vicinity of a smelting complex contaminated by heavymetals and the other at a relatively uncontaminated site, and (ii) two groups of oak saplings at the uncontaminated site, one of which was sprayed with zinc, lead, and cadmium to simulate the heavymetal pollution from the smelter without the complicating effects of other pollutants. Total viable counts of bacteria, yeasts, and filamentous fungi (isolated by leaf washing) were generally little affected by the spraying treatment, whereas polluted leaves of mature trees supported fewer bacteria compared with leaves of mature trees at the uncontaminated site. Numbers of pigmented yeasts were lower on polluted oaks and on metal-dosed saplings compared with their respective controls. Polluted leaves of mature trees supported both greater numbers of Aureobasidium pullulans and Cladosporium spp. and a greater percentage of metal-tolerant fungi compared with oak leaves at the uncontaminated site. There were no significant overall differences in the degree of mycelial growth between the two groups of saplings or the mature trees.

The use of plants for rehabilitation of heavy-metal-contaminated environments is an emerging area of interest because it provides an ecologically sound and safe method for restoration and remediation. Although a number of plant species are capable of hyperaccumulation of heavymetals, the technology is not applicable for remediating sites with multiple contaminants. A clever solution is to combine the advantages of microbe-plant symbiosis within the plant rhizosphere into an effective cleanup technology. We demonstrated that expression of a metal-binding peptide (EC20) in a rhizobacterium, Pseudomonas putida 06909, not only improved cadmium binding but also alleviated the cellular toxicity of cadmium. More importantly, inoculation of sunflower roots with the engineered rhizobacterium resulted in a marked decrease in cadmium phytotoxicity and a 40% increase in cadmium accumulation in the plant root. Owing to the significantly improved growth characteristics of both the rhizobacterium and plant, the use of EC20-expressing P. putida endowed with organic-degrading capabilities may be a promising strategy to remediate mixed organic-metal-contaminated sites. PMID:16461658

The heavymetal tolerant Cardaminopsis halleri, grown on Zn and Cu polluted soil, showed electron dense metal containing precipitates (Zn, Cu, Sn, Fe, Al) on the leaf surface, in the intercellular spaces (Zn, Cu, Sn), the cell walls and the cell wall thickenings of the xylem vessels (Zn, traces of Cu and Fe). Large amounts of Zn were measured in the vacuoles, the main storage compartment for this metal in Cardarminopsis. The cytoplasm and nuclei contained small precipitates, including mainly Zn and Si. As shown by ESI Zn was co-localized with Si in these structures. The EEL-spectra of the cytoplasmic precipitates corresponded with the spectra of Zn-silicate. Besides Zn-silicate, electron translucent structures in the cytoplasm were identified as SiO2 by their EEL spectra. It was concluded that in the cytoplasm of Cardaminopsis Zn is transiently accumulated as silicate, being slowly degraded to SiO2. Zn is translocated into the vacuole and accumulated in an unknown form. A second Si and Zn-uptake mechanism was found, excluding a membrane and cytoplasm passage. Pinocytotic vesicles, formed by the plasmamembrane and the tonoplast, enable a direct translocation of Si and Zn from extracellular compartments into the vacuole. The formation of Zn-silicate is part of the heavymetal tolerance mechanism and may be responsible for the amelioration of the Zn toxicity in Cardaminopsis. PMID:11314953

During the growing season, comparisons were made of the leaf surface microflora of (i) two groups of mature oak trees, one in the vicinity of a smelting complex contaminated by heavymetals and the other at a relatively uncontaminated site, and (ii) two groups of oak saplings at the uncontaminated site, one of which was sprayed with zinc, lead, and cadmium to simulate the heavymetal pollution from the smelter without the complicating effects of other pollutants. Total viable counts of bacteria, yeasts, and filamentous fungi (isolated by leaf washing) were generally little affected by the spraying treatment, whereas polluted leaves of mature trees supported fewer bacteria compared with leaves of mature trees at the uncontaminated site. Numbers of pigmented yeasts were lower on polluted oaks and on metal-dosed saplings compared with their respective controls. Polluted leaves of mature trees supported both greater numbers of Aureobasidium pullulans and Cladosporium spp. and a greater percentage of metal-tolerant fungi compared with oak leaves at the uncontaminated site. There were no significant overall differences in the degree of mycelial growth between the two groups of saplings or the mature trees. PMID:16345669

Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavymetals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavymetals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavymetals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavymetal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavymetals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavymetals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavymetals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavymetals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine. PMID:14753260

In this report, we have described the principal stages of a two-step process for the in-situ stabilization of actinide ions in the environment. The combination of cation exchange and mineralization appears likely to provide a long-term solution to environments contaminated with heavymetals. Relying on a naturally occurring sequestering agent has obvious potential advantages from a regulatory standpoint. There are additional aspects of this technology requiring further elucidation, including the demonstration of the effect of these treatment protocols on the geohydrology of soil columns, further examination of the influence of humates and other colloidal species on cation uptake, and microbiological studies of phytate hydrolysis. We have learned during the course of this investigation that phytic acid is potentially available in large quantities. In the US alone, phytic acid is produced at an annual rate of several hundred thousand metric tons as a byproduct of fermentation processes (11). This material presently is not isolated for use. Instead, most of the insoluble phyate (as phytin) is being recycled along with the other solid fermentation residues for animal feed. This material is in fact considered undesirable in animal feed. The details of possible separation processes for phytate from these residues would have to be worked out before this untapped resource would be available for application to heavymetal sequestration. The results described emphasize the behavior of actinide and trivalent lanthanide metal ions, as these species are of primary interest to the Department of Energy for the cleanup of the former nuclear weapons production complex. While the specific demonstration includes this limited selection of metal ions, the technique should be readily applicable to any class of metal ions that form insoluble phosphate compounds under appropriate conditions. Further, though this demonstration has been conducted in the pH 5-8 range, it is conceivable that

The current state of the art regarding the use of chelating agents to extract heavymetal contaminants has been addressed. Results are presented for treatability studies conducted as worst-case and representative soils from Aberdeen Proving Ground's J-Field for extraction of copper (Cu), lead (Pb), and zinc (Zn). The particle size distribution characteristics of the soils determined from hydrometer tests are approximately 60% sand, 30% silt, and 10% clay. Sequential extractions were performed on the 'as-received' soils (worst case and representative) to determine the speciation of the metal forms. The technique speciates the heavymetal distribution into an easily extractable (exchangeable) form, carbonates, reducible oxides, organically-bound, and residual forms. The results indicated that most of the metals are in forms that are amenable to soil washing (i.e. exchangeable+carbonate+reducible oxides). The metals Cu, Pb, Zn, and Cr have greater than 70% of their distribution in forms amenable to soil washing techniques, while Cd, Mn, and Fe are somewhat less amenable to soil washing using chelant extraction. However, the concentrations of Cd and Mn are low in the contaminated soil. From the batch chelant extraction studies, ethylenediaminetetraacetic acid (EDTA), citric acid, and nitrilotriacetic acid (NTA) were all effective in removing copper, lead, and zinc from the J-Field soils. Due to NTA being a Class II carcinogen, it is not recommended for use in remediating contaminated soils. EDTA and citric acid appear to offer the greatest potential as chelating agents to use in soil washing the Aberdeen Proving Ground soils. The other chelating agents studied (gluconate, oxalate, Citranox, ammonium acetate, and phosphoric acid, along with pH-adjusted water) were generally ineffective in mobilizing the heavymetals from the soils. The chelant solution removes the heavymetals (Cd, Cu, Pb, Zn, Fe, Cr, As, and Hg) simultaneously. Using a multiple-stage batch extraction

A bioelectrochemical method for the determination of heavymetal ions has been developed. This method is based on the inhibition effect of metal ions on the enzymatic activity of oxidase enzymes. The enzymatic activity was determined with an amperometric hydrogen peroxide probe. The inhibition effect on enzymes in solution and covalently immobilized on polymeric supports has been evaluated. Hg(II) was the metal ion that inhibited almost all the enzymes, particularly glycerol-3-P oxidase. Hg(II) was detected in the 0.05/0.5 ppm range with the enzyme in solution. Calibration curves for Hg(II) were also obtained with the other oxidase enzymes in the 0.5/10 ppm range. The other metal ions tested inhibited the enzymes more specifically. The metal ion/enzyme systems which gave the best inhibition were Se(IV)/glutathione oxidase, Ni(II)/sarcosine oxidase, V(V)/glutathione oxidase, Cu(II)/alcohol oxidase from Pichia Pastoris and Cd(II)/D-aminoacid oxidase. All these metal ions were detected in the 0.1/10 ppm range using the enzymes in solution or covalently immobilized.

A bioelectrochemical method for the determination of heavymetal ions has been developed. This method is based on the inhibition effect of metal ions on the enzymatic activity of oxidase enzymes. The enzymatic activity was determined with an amperometric hydrogen peroxide probe. The inhibition effect on enzymes in solution and covalently immobilized on polymeric supports has been evaluated. Hg(II) was the metal ion that inhibited almost all the enzymes, particularly glycerol-3-P oxidase. Hg(II) was detected in the 0.05/0.5 ppm range with the enzyme in solution. Calibration curves for Hg(II) were also obtained with the other oxidase enzymes in the 0.5/10 ppm range. The other metal ions tested inhibited the enzymes more specifically. The metal ion/enzyme systems which gave the best inhibition were Se(IV)/glutathione oxidase, Ni(II)/sarcosine oxidase, V(V)/glutathione oxidase, Cu(II)/alcohol oxidase from Pichia Pastoris and Cd(II)/D-amino acid oxidase. All these metal ions were detected in the 0.1/10 ppm range using the enzymes in solution or covalently immobilized.

Biochar has been intensively investigated over recent years, not only as a promising carbon sequestration or fertilizing agent in soils but also as a possible new sorbent to remediate contaminated soils. A few studies have revealed its high potential for heavymetals immobilization depending on the nature of biochar and trace elements. The mechanisms behind this immobilization remain however unclear: some authors have hypothesized a high sorption capacity due to biochar large surface area while others have suggested that this immobilization is mainly due to soil pH increase. In particular, the distinction between heavymetals specific sorption in biochar pores and heavymetals precipitation in or outside biochar particles is often impossible to make while it is of primary importance to evaluate biochar ability to retain these pollutants on a long-time scale. In order to evaluate the main heavymetal immobilization effects on a standard biochar and to identify the most successful biochar parts of the sample, we examined biochar particles after heavymetals immobilization in batch experiments designed to mimic real chemical processes in soils. A biochar derived from hard and soft wood and pyrolyzed at about 450°C was put in contact with relatively low concentrations of heavymetals (Pb, Cu, Cd, Zn, Ni) in an initially acidic Ca(NO3)2 solution. Following a one-week adsorption and a one-week desorption step, we recovered the biochar particles and observed them using scanning electron microscopy coupled to energy dispersive x-ray spectroscopy, focusing especially on the changes in mineral phases and the location of each of the retained heavymetals on biochar particles. We were able to distinguish different structures in the biochar samples which were linked to the degree of pyrolysis and the exact nature of the raw wood biomass. We detected the presence of concentrated metals zones (e.g. lead) in specific locations of the organic particles depending on the original

Heavymetal (Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se and Zn) concentration in sixty-six groundwater samples of the West Bokaro coalfield were analyzed using inductively coupled plasma-mass spectroscopy for determination of seasonal fluctuation, source apportionment and heavymetal pollution index (HPI). Metal concentrations were found higher in the pre-monsoon season as compared to the post-monsoon season. Geographic information system (GIS) tool was attributed to study the metals risk in groundwater of the West Bokaro coalfield. The results show that 94 % of water samples were found as low class and 6 % of water samples were in medium class in the post-monsoon season. However, 79 % of water samples were found in low class, 18 % in medium class and 3 % in high class in the pre-monsoon season. The HPI values were below the critical pollution index value of 100. The concentrations of Al, Fe, Mn, and Ni are exceeding the desirable limits in many groundwater samples in both seasons. PMID:26886427

Desmodesmus communis LUCC 002 was cultivated using flue gas originating from a coal-fired power plant as a carbon dioxide (CO2) source. The flue gas contains various heavymetals. For investigating the fate of flue-gas-introduced metals on the cultivation system, bioaccumulation was measured in the microalgal biomass and milieu. The accumulated biomass was found to contain eight heavymetals: arsenic, chromium, barium, lead, selenium, silver, cadmium, and mercury. High heavymetal accumulations were also found in the control group of algae grown without the addition of flue gas at the same location. Further testing revealed that some of the heavymetals originated from well water used in the cultivation. The flue-gas-influenced bioaccumulation pattern of different heavymetals was observed. The responses of individual heavymetals and the influence of well water microbial flora on the algal growth were investigated, this study showed that hormesis was developed by the D. communis LUCC 002. PMID:25184415

A novel method that uses the aqueous sodium alginate solution for direct gelation with metal ions is developed for effective removal and recovery of heavymetals from industrial wastewater. The experimental study was conducted on Pb(2+), Cu(2+), and Cd(2+) as the model heavymetals. The results show that gels can be formed rapidly between the metals and alginate in less than 10min and the gelation rates fit well with the pseudo second-order kinetic model. The optimum dosing ratio of alginate to the metal ions was found to be between 2:1 and 3:1 for removing Pb(2+) and around 4:1 for removing Cu(2+) and Cd(2+) from wastewater, and the metal removal efficiency by gelation increased as the solution pH increased. Alginate exhibited a higher gelation affinity toward Pb(2+) than Cu(2+) and Cd(2+), which allowed a selective removal of Pb(2+) from the wastewater in the presence of Cu(2+) and Cd(2+) ions. Chemical analysis of the gels suggests that the gelation mainly occurred between the metal ions and the COO(-) and OH groups on alginate. By simple calcination of the metal-laden gels at 700°C for 1h, the heavymetals can be well recovered as valuable resources. The metals obtained after the thermal treatment are in the form of PbO, CuO, and CdO nanopowders with crystal sizes of around 150, 50, and 100nm, respectively. PMID:26808245

An innovative wet-treatment with Na2 S transforms two indium metal-organic frameworks (MOFs) into a series of porous inorganic sorbents. These MOF-templated materials display remarkable affinity for heavymetals with saturation occurring in less than 1 h. The saturation capacity for Hg(II) exceeds 2 g g(-1) , more than doubling the best thiol-functionalized sorbents in the literature. PMID:25348588

Urban soils (Anthrosols, Technosols, and the remaining natural patches) are essential components of the city ecosystems influencing the quality of life for people. Unfortunately, because of the high concentration of matter and energy that occurs in any city, these soils might accumulate potentially toxic pollutants such as heavymetals, organic compounds, pathogens, pharmaceuticals, and soluble salts. Contamination by heavymetals has been considered especially dangerous because they can affect human health via inhalation of dust, ingestion, or skin contact with soils. Children are the more exposed citizens in gardens and parks. Accordingly, our objective was to analyze the content of heavymetals in soils of the two most emblematic, extensive, and visited landscaped areas of the Granada city (Salón Garden, which dates back to 1612, and Federico García Lorca Park, opened since 1993) for assessing the health hazard. Using a composite sampling of 20-30 points chosen at random, we collected the upper soil (10 cm) of five representative plots for each landscaped area. We determined soil characteristics by routine procedures and metal elements using ICP-mass. From high to low concentration we found Mn, Ba, Pb, Zn, V, Sn, Cr, Cu, Ni, Sb, Y, As, Sc, Co, Th, Au, U, Mo, Be, Bi, Tl, Cd, and In; the first 10 metals ranging between 478 and 22 ppm. Mn, Ba, and other trace elements were strongly correlated with soil properties suggesting the inheritance as a possible source of metal variation, especially in the soils of younger Park, where the materials used to build gardens in the five sampled plots seemed to be more variable (carbonates: 10-40%, clay: 18-26%, pH: 7.6-7.9, organic matter: 3-7%, free iron 0.5-1.1%). The content of many other metals measured in the sampled plots, however, were independent of soil material and management. On the other hand, compared to agricultural and native soils of the surroundings, our urban soils had obviously greater content in organic

Though seaweed consumption is growing steadily across Europe, relatively few studies have reported on the quantities of heavymetals they contain and/or their potential effects on the population's health. This study focuses on the first topic and analyses the concentrations of six typical heavymetals (Cd, Pb, Hg, Cu, Zn, total As and inorganic As) in 52 samples from 11 algae-based products commercialised in Spain for direct human consumption ( Gelidium spp.; Eisenia bicyclis; Himanthalia elongata; Hizikia fusiforme; Laminaria spp.; Ulva rigida; Chondrus crispus; Porphyra umbilicales and Undaria pinnatifida). Samples were ground, homogenised and quantified by atomic absorption spectrometry (Cu and Zn by flame AAS; Cd, Pb and total As by electrothermal AAS; total mercury by the cold vapour technique; and inorganic As by flame-hydride generation). Accuracy was assessed by participation in periodic QUASIMEME (Quality Assurance of Information in Marine Environmental Monitoring in Europe) and IAEA (International Atomic Energy Agency) intercalibration exercises. To detect any objective differences existing between the seaweeds' metal concentrations, univariate and multivariate studies (principal component analysis, cluster analysis and linear discriminant analysis) were performed. It is concluded that the Hizikia fusiforme samples contained the highest values of total and inorganic As and that most Cd concentrations exceeded the French Legislation. The two harvesting areas (Atlantic and Pacific oceans) were differentiated using both univariate studies (for Cu, total As, Hg and Zn) and a multivariate discriminant function (which includes Zn, Cu and Pb).

Primary extranodal Non-Hodgkin lymphoma (NHL) is a non epithelial tumours that accounts for 40% of cases of NHL. Spread of nodal lymphomas to the gastrointestinal tract (GIT) is the most common location. Within the GIT is the stomach the most affected organ (60%). We report the case of 52-year- old man , mining company worker for over 10 years, which is derived to the Service of Gastroenterology with history of epigastric pain, nausea, vomiting and weight loss. Upper gastrointestinal endoscopic examination revealed an ulcerated lesion on greater curve of stomach and histopathological examination and subsequent immunohistochemical analysis showed diffuse large B cell gastric NHL. Also, the patient had multiple organ involvement in relation to chronic exposure to heavymetals, which was found in the mineralograma, with the highest concentration of uranium, thallium, arsenic, lead and mercury. The literature has described the association of chronic occupational exposure to uranium and arsenic with NHL presenting gastrointestinal involvement. Therefore, gastric commitment can not be considered as an isolated injury, but rather part of systemic involvement associated with elevated concentrations of metals. Mining is a key driver of income for Peru; however, there are no reports to date of the association of gastrointestinal NHL commitment regarding occupational exposure to heavymetals. PMID:23307094

The principal objective of this report is to identify and prioritize heavymetal-containing wastewaters at the Savannah River Site (SRS) in terms of their suitability for testing of and clean-up by a novel bioremediation process being developed by SRTC. This process involves the use of algal biomass for sequestering heavymetal and radionuclides from wastewaters. Two categories of SRS wastewaters were considered for this investigation: (1) waste sites (primarily non-contained wastes managed by Environmental Restoration), and (2) waste streams (primarily contained wastes managed by Waste Management). An attempt was made to evaluate all sources of both categories of waste throughout the site so that rational decisions could be made with regard to selecting the most appropriate wastewaters for present study and potential future treatment. The investigation included a review of information on surface and/or groundwater associated with all known SRS waste sites, as well as waters associated with all known SRS waste streams. Following the initial review, wastewaters known or suspected to contain potentially problematic concentrations of one or more of the toxic metals were given further consideration.

Analysis of ten heavymetals (Ag, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Zn) in six sediment cores from Wellington Harbour show both anthropogenic enrichments and diagenetic modifications. Absolute concentrations determined by two methods, x-ray fluorescence and acid leaching for bioavailability, are not comparable. However, vertical trends in concentrations of the cored sediment are comparable. To assess levels of anthropogenic pollution, enrichment factors (enriched concentrations in upper core divided by background levels in lower core) are preferred over index of accumulation ( I geo) values because preindustrial or background levels of heavymetals are well constrained. The ten metals are placed into three groups: (1) Cu, Pb, and Zn, which show the most anthropogenic enrichment; (2) As, Cd, Cr, Ni, and Sb, which are often associated with anthropogenic pollution but show only minor enrichment; and (3) Fe and Mn, which are diagenetically enriched. Assuming harbor waters are well mixed, anthropogenic enrichments of Cu, Pb, and Zn, are time correlative, but the degree of enrichment depends on the method of analysis and core location. Levels of As, Cd, Pb, and Zn show small variations in preindustrial sediments that are not related to changes in grain size and probably result from changes in the oxidation-reduction potential of the sediments and salinity of the pore waters.

The aim of the present 1-year study was to investigate the effect of heavymetals in synthetic fertilizers on water and sediment quality in the Seyfe Lake, where agricultural activity was the only anthropogenic source. Metal concentrations of five different types of synthetic fertilizers used in agricultural fields within the Seyfe Lake closed basin were as follows: Zn > Pb > Cu > Cr > Cd > As > Ni > Co. The annual average of heavymetal concentrations in the sediment samples were as follows: Zn > Pb > As > Cr > Ni > Cu > Cd > Co. Seyfe Lake sediment was classified as anthropogenically "highly polluted" in terms of the As and Zn concentrations at each sample station based on the sediment quality guidelines. Furthermore, the sediment could be classified as "moderately to highly polluted" in terms of the As concentration, based on the geo-accumulation index. PMID:26744023

Soils around mine and in urban areas are often contaminated by heavymetals derived from industrial and human activities [1, 2]. These contaminated soils are often characterized by a magnetic enhancement on topsoils. Many studies demonstrated that there are significant correlations between heavymetals and various magnetic parameters in contaminated soils, indicating a strong affinity of heavymetals to magnetic minerals. The magnetic particles in contaminated soils were separated by a magnetic separation technique. The rock magnetism, XRD, field emission scanning electron microscopy equiped with an energy-dispersive X-ray analyzer (FESEM/EDX) were used to characterize their magnetic mineralogy. Results of XRD analysis indicated that the magnetic particles separated from heavymetal-contaminated soils are composed of quartz, magnetite, and hematite. Based on the X-ray diffraction peak intensity, the Fe3O4 was identified as the predominant magnetic mineral phase. The high-temperature magnetization (Ms-T) curves of magnetic particles extracted from contaminated soils show a sharp Ms decrease at about 580C (the Curie temperature of magnetite), suggesting that magnetite is the dominant magnetic carrier. The hysteresis loops of contaminated soils are closed at about 100-200 mT which is consistent with the presence of a dominant ferrimagnetic mineral phase. The FESEM analysis showed a great variety of shapes of magnetic particles in contaminated soils. The most common morphology are observed in the form of spherules, with the sizes ranging from 20 to 100 um. The chemical composition of magnetic particles consist mainly of Fe, Si, Al, and Ca with minor heavymetal elements (Cu, Zn, Hg, and Cr). The semi-quantitative Fe content identified by FESEM/EDX ranged from 40 to 90%. Combined studies of rock magnetism, XRD, and FESEM/EDX indicated that magnetic mineral phases responsible for the magnetic enhancement of contaminated soils are anthropogenic origin which are coarse

Nanosized metal oxides (NMOs), including nanosized ferric oxides, manganese oxides, aluminum oxides, titanium oxides, magnesium oxides and cerium oxides, provide high surface area and specific affinity for heavymetal adsorption from aqueous systems. To date, it has become a hot topic to develop new technologies to synthesize NMOs, to evaluate their removal of heavymetals under varying experimental conditions, to reveal the underlying mechanism responsible for metal removal based on modern analytical techniques (XAS, ATR-FT-IR, NMR, etc.) or mathematical models, and to develop metal oxide-based materials of better applicability for practical use (such as granular oxides or composite materials). The present review mainly focuses on NMOs' preparation, their physicochemical properties, adsorption characteristics and mechanism, as well as their application in heavymetal removal. In addition, porous host supported NMOs are particularly concerned because of their great advantages for practical application as compared to the original NMOs. Also, some magnetic NMOs were included due to their unique separation performance. PMID:22018872

There are increasing concerns on heavymetal contaminant in soils and vegetables. In this study, we investigated heavymetal pollution in vegetables and the corresponding soils in the main vegetable production regions of Zhejiang province, China. A total of 97 vegetable samples and 202 agricultural soil samples were analyzed for the concentrations of Cd, Pb, As, Hg, and Cr. The average levels of Cd, Pb, and Cr in vegetable samples [Chinese cabbage (Brassica campestris spp. Pekinensis), pakchoi (Brassica chinensis L.), celery (Apium graveolens), tomato (Lycopersicon esculentum), cucumber (Colletotrichum lagenarium), cowpea (Vigna unguiculata), pumpkin (Cucurbita pepo L.), and eggplant (Solanum melongena)] were 0.020, 0.048, and 0.043 mg kg(-1), respectively. The Pb and Cr concentrations in all vegetable samples were below the threshold levels of the Food Quality Standard (0.3 and 0.5 mg kg(-1), respectively), except that two eggplant samples exceeded the threshold levels for Cd concentrations (0.05 mg kg(-1)). As and Hg contents in vegetables were below the detection level (0.005 and 0.002 mg kg(-1), respectively). Soil pollution conditions were assessed in accordance with the Chinese Soil Quality Criterion (GB15618-1995, Grade II); 50 and 68 soil samples from the investigated area exceeded the maximum allowable contents for Cd and Hg, respectively. Simple correlation analysis revealed that there were significantly positive correlations between the metal concentrations in vegetables and the corresponding soils, especially for the leafy and stem vegetables such as pakchoi, cabbage, and celery. Bio-concentration factor values for Cd are higher than those for Pb and Cr, which indicates that Cd is more readily absorbed by vegetables than Pb and Cr. Therefore, more attention should be paid to the possible pollution of heavymetals in vegetables, especially Cd. PMID:26013654

Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavymetals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavymetals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and

Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavymetals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavymetals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and

Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavymetals in street dust. This study investigated heavymetal concentrations in street dust samples collected from different types of markets. It compared the results with heavymetal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavymetals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu), lead (Pb) and zinc (Zn). Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavymetals in heavy traffic road and fish market dust had different sources. Relatively high heavymetal concentration in street dust from the fish market may negatively affect worker's mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavymetal concentrations in street dust and worker's health in traditional marketplaces should be conducted to elucidate the effect of heavymetals on psychological health in humans. PMID:27529268

Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavymetals in street dust. This study investigated heavymetal concentrations in street dust samples collected from different types of markets. It compared the results with heavymetal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavymetals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu), lead (Pb) and zinc (Zn). Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavymetals in heavy traffic road and fish market dust had different sources. Relatively high heavymetal concentration in street dust from the fish market may negatively affect worker’s mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavymetal concentrations in street dust and worker’s health in traditional marketplaces should be conducted to elucidate the effect of heavymetals on psychological health in humans. PMID:27529268

Norway has the following priorities for management of municipal solid waste (MSW) (1) Reduce waste generation and toxic components in waste, (2) Encourage re-use, recycling and energy recovery, and (3) Secure an environmentally safe management of residues. MSW consists of household waste and waste from the service and trade industry delivered to municipal waste treatment plants or recycling schemes. In 1995, a total of 2.7 million tons of MSW (1.26 million tons of household waste and 1.44 million tons of waste from service and trade industry) was handled as follows: 68% was deposited on landfills, 18% was combusted, 13% recycled and 1% composted. Combustion of MSW is handled in five larger plants with energy recovery located in different cities in Norway. In addition, a new incinerator for MSW is planned. This incinerator will have to meet the new emission regulations given by the European Union which are more stringent than the present regulations. Hence, Norway is moving towards more stringent regulations, leading to an increased interest in the environmental aspects of MSW incinerators. During 1995 Trondheim Energy Company carried out an investigation program to examine the residues from the incinerator. Primary attention was on the heavymetals in the bottom ash, fly ash and the landfill leacate. The program was conducted in order to establish more information about characteristics of the residues and thus be able to undertake a sounder evaluation of the environmental aspects of the final treatment of these products. This program was supplementary to the emission analysis done periodically for the flue gas and drain water. The objective of this work has been to establish knowledge about the partitioning of heavymetals through the incinerator and calculate the concentrations of heavymetal in the input MSW.

Wild rice grain samples from various parts of the world have been found to have elevated concentrations of heavymetals, raising concern for potential effects on human health. It was hypothesized that wild rice from north-central Wisconsin could potentially have elevated concentrations of some heavymetals because of possible exposure to these elements from the atmosphere or from water and sediments. In addition, no studies of heavymetals in wild rice from Wisconsin had been performed, and a baseline study was needed for future comparisons. Wild rice plants were collected from four areas in Bayfield, Forest, Langlade, Oneida, Sawyer and Wood Counties in September, 1997 and 1998 and divided into four plant parts for elemental analyses: roots, stems, leaves and seeds. A total of 194 samples from 51 plants were analyzed across the localities, with an average of 49 samples per part depending on the element. Samples were cleaned of soil, wet digested, and analyzed by ICP for Ag, As, Cd, Cr, Cu, Hg, Mg, Pb, Se and Zn. Roots contained the highest concentrations of Ag, As, Cd, Cr, Hg, Pb, and Se. Copper was highest in both roots and seeds, while Zn was highest just in seeds. Magnesium was highest in leaves. Seed baseline ranges for the 10 elements were established using the 95% confidence intervals of the medians. Wild rice plants from northern Wisconsin had normal levels of the nutritional elements Cu, Mg and Zn in the seeds. Silver, Cd, Hg, Cr, and Se were very low in concentration or within normal limits for food plants. Arsenic and Pb, however, were elevated and could pose a problem for human health. The pathway for As, Hg and Pb to the plants could be atmospheric.

The paper suggests a methodology to represent overall soil pollution in a sampled area using continuous limitation scores. The interpolated heavymetal concentrations are first transformed to limitation scores using the exponential transfer function determined by using two threshold values: permissible concentration (0 limitation points) and seriously polluted soil (4 limitation points). The limitation scores can then be summed to produce the map of cumulative limitation scores and visualize the most critically polluted areas. The methodology was illustrated using the 784 soil samples analyzed for Cd, Cr, Cu, Ni, Pb and Zn in the central region of Croatia. The samples were taken at 1×1 and 2×2 km grids and at fixed depths of 20 cm. Heavymetal concentrations in soil were determined by ICP-OES after microwave assisted aqua regia digestion. The sampled concentrations were interpolated using block regression-kriging with geology and land cover maps, terrain parameters and industrialization parameters as auxiliary predictors. The results showed that the best auxiliary predictors are geological map, ground water depth, NDVI and slope map and distance to urban areas. The spatial prediction was satisfactory for Cd, Ni, Pb and Zn, and somewhat less satisfactory for Cu and Cr. The final map of cumulative limitation scores showed that 33.5% of the total area is suitable for organic agriculture and 7.2% of the total area is seriously polluted by one or more heavymetals. This procedure can be used to assess suitability of soils for agricultural production and as a basis for possible legal commitments to maintain the soil quality.

Metal ions are not only valuable intermediates in metal extraction, but also important raw materials for technical applications. They possess some unique but, identical physical and chemical properties, which make them useful probes of low temperature geochemical reactions. Heavymetals are natural constituents of the earth's crust, but indiscriminate human activities have drastically altered their geochemical cycles and biochemical balance. Metal concentration in soil typically ranges from less than one to as high as 100,000 mg/kg. Heavymetal contaminations of land resources continue to be the focus of numerous environmental studies and attract a great deal of attention worldwide. This is attributed to no--biodegradability and persistence of heavymetals in soils. Prolonged exposure to heavymetals such as cadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Complexation, separation, and removal of metal ions have become increasingly attractive areas of research and have led to new technical developments like phytoremediation that has numerous biotechnological implications of understanding of plant metal accumulation. Croton bonplandianum is newly identified as a potential heavymetal hypreaccumulator. In this study Croton bonplandianum was subjected for in vitro heavymetal accumulation, to explore the accumulation pattern of four heavymetals viz Cadmium, Lead, Nickel and Zinc in various parts of Croton bonplandianum plant parts. It was found that the efficiency of Croton bonplandianum to accumulate heavymetals is Cd>Pb>Zn>Ni. The absorption of these heavymetals in plant parts revealed that the highest translocation of metals from ground to root was ground to be in the order of Pb (1.12) > Zn (0.26) > Ni (0.18) > Cd (0.15). The distribution of Cd in Croton bonplandianum followed the trend Root>Stem>Leaf; with Ni it was Root>Leaf>Stem, while Pb showed leaf>stem>root. Translocation of metals in Croton bonplandianum plant parts

Accumulation rates of heavymetals (Cd, Cr, Cu, Mn, Pb, and Zn) retained in wetland sediments in northwest Indiana-downwind of the Chicago-Gary-Hammond industrial area-are quantified to assess anthropogenic influences on atmospheric fluxes. Metal concentrations for 22 sediment cores are determined by ICP-AES after ashing and strong acid extraction. Relations between organic content and metal concentrations at depth are used to separate natural and anthropogenic sources. Accumulation rates over the lifetime of the wetlands (???4500 years) have averaged 0.2 (Cd), 1.4 (Cu), 1.7 (Cr), 13.4 (Mn), 4.8 (Pb), and 18.7 (Zn) mg m-2 y-1. Rates for the last 100 years have increased on average by factors of 6 (Cd), 8 (Cu), 10 (Mn), 15 (Pb), and 30 (Zn), remaining effectively constant for Cr. Where the wetlands have been drained, metals have been lost from the sediments, owing to changes in organic content and local hydrochemistry (exposure to acidic rainfall). Sediment-based accumulation rates at the undrained sites are higher, though generally consistent, with measured and modeled atmospheric fluxes documented by short-term studies conducted over the last three decades. The fraction of the total metals in the wetlands estimated to be of anthropogenic origin ranges from approximately 3% for Cr, up to approximately 35% for Pb, and 70% for Zn. This historic legacy of contamination must be considered in land management decisions, particularly when wetlands are drained.

A novel hydrate-based method is proposed for separating heavymetal ions from aqueous solution. We report the first batch of experiments and removal characteristics in this paper, the effectiveness and feasibility of which are verified by Raman spectroscopy analysis and cross-experiment. 88.01-90.82% of removal efficiencies for Cr3+, Cu2+, Ni2+, and Zn2+ were obtained. Further study showed that higher R141b-effluent volume ratio contributed to higher enrichment factor and yield of dissociated water, while lower R141b-effluent volume ratio resulted in higher removal efficiency. This study provides insights into low-energy, intensive treatment of wastewater.

The "sampling intensity" issue is of important application to precision agriculture. About 80%-85 % of the total error in precision in agriculture results from the field sampling preceding the application of fertilizers and corrective practices. The spatial sampling design used to characterize the spatial variability of soil attributes is crucial to science studies. The sample planning for interpolation of a regionalized variable may use several criteria, which could be best selected from the estimated semivariogram from a previously established grid. The objective of this study was to evaluate the use of the semivariogram scaled to improve the sample design of heavymetals in an experimental plot. The study area surface is 6 ha and is located at Castro Ribeiras de Lea, Lugo, Spain. The geographical coordinates of the study area are: latitude 43° 09 '49''N and longitude 7° 29' 47''W, with average elevation of 410 m and average slope of 2 %. The mean annual temperature is 11.2 °C and mean annual rainfall is 930 mm (data 1961-1990). The soil is classified with Cambisol and the parent material are sediments from tertiary and quaternary. Heavymetals were initially sampled at 40 points randomly distributed in the study area. The heavymetals analyzed in this study were: Pb, Cd, Cu and Ni. Data were initially analyzed using descriptive statistics and geostatistical tools. The scaled semivariogram was built with the aim of setting a single theoretical semivariogram all elements studied. Subsequently, the software SANOS was used to determine the sampling optimization of new sampling points of the heavymetals. The spatial variability analysis of the studied elements using the scaled semivariogram showed the existence of a relationship between the spatial variability of these elements. The gaussian model was adjusted for Pb, Cd and Ni, and spherical models for the Cu element. The semivariogram scaled theoretical adjusted to elements in four study was Gaussian, with a

The goals of this study were to elucidate relationships between food habits and tissue accumulations of heavymetals in Chesapeake Bay waterfowl and to determine effects of chronic cadmium and lead ingestion on energy metabolism in waterfowl. In combination with an imposed food restriction, cadmium ingestion appeared to alter some indices of energy metabolism, such as plasma concentrations of free fatty acids and triiodothyronine, at dietary cadmium levels far below those eliciting similar responses in the absence of a food restriction. Those results suggest the importance of considering interactions with other stressors when examining potential effects of environmental contaminants on wild animals.

Vegetables are an inevitable and important part of a healthy and balanced diet. They could be contaminated by heavymetals in many ways including irrigation by sewage water and industrial effluents sewage sludge, vehicular emissions, industrial waste and atmospheric deposition. In this study, we sought to determine if some vegetables (cucumbers, tomatoes, cabbage, lettuce, potatoes, onions, carrots, persian leeks, dill, spinach, coriander, parsley) grown locally in the suburban of Isfahan city and sold in the urban markets are contaminated with cadmium (Cd), chromium (Cr) and lead (Pb). Vegetables were sampled from August to October 2010. After washing, they were oven-dried and digested using three-acid mixture (70% HNO3, 65% HClO4 and 70% H2SO4). Analyzes of the heavymetals was performed using atomic absorption spectrophotometry. To validate the assay method, intra-day and inter-day variation studies were performed. The concentrations (μg/g) of heavymetals in the samples ranged from 0.00 to 3.66 for Cd, 0.00 to 6.00 for Cr and 0.00 to 7.14 for Pb. The highest concentration of heavymetals was for Pb. The results showed that the amount of Cd, Cr and Pb of some samples exceeded the recommended levels. The amount of Cd in cucumber, tomatoes, potatoes with skin, carrots, and spinach was significantly higher in the samples collected from Isfahanak, Dashti and Ilchi farms than those of Dorche farms. Also, the amount of Cr in onion, carrots, and spinach was significantly higher in samples collected from Isfahanak, Dashti and Ilchi farms than those of Dorche farms. However, the amount of Pb in the carrots and leek was significantly higher in the samples collected from Dorche farms than those of Isfahanak, Dashti and Ilchi farms. It can be concluded from the findings of this study that the amounts of Cd, Cr, and Pb were higher than the acceptable levels recommended by WHO/FAO. Also, higher amount of Cd and Cr in some samples collected from Isfahanak, Dashti and Ilchi

Concentration of HeavyMetals (Cd, Cr, Fe, Ni) in water, plants and sediments of river Yamuna flowing in Haryana through Delhi are reported here selecting 14 stations covering the upstream and downstream sites of major industrial complexes of the State. Some important characteristics of river water and sediments (pH, EC, Cl(-), SO(3)(2-), and PO(4)(3-) in water and sediments, COD of water and organic matter content of sediments) were also analysed and inter-relationships of all these parameters with heavymetal concentration in different compartments were examined. The sediments of the river show significant enrichment with Cd and Ni indicating inputs from industrial sources. Concentrations of Cr are moderate and show high enrichment values only at a few sites. Enrichment factor for Fe is found to be <1, showing insignificant effect of anthropogenic flux. Concentrations of these metals in river water are generally high exceeding the standard maximum permissible limits prescribed for drinking water, particularly in the downstream sites. The aquatic plants show maximum accumulation of Fe. The other heavymetals Cd, Cr and Ni, though less in concentration, show some accumulation in the plants growing in contaminated sites. Interrelationships of metal concentration with important characteristics of water and sediment have been analysed. Analysis of heavymetals in water, sediments and littoral flora in the stretch of river Yamuna is first study of itself and interrelationship of metal concentration and other important characteristics make the study significant and interesting in analysing the pollution load at different points of the river body. PMID:18809251

Lichens are useful monitoring organisms for heavymetal pollution. They are high in carbon based secondary compounds (CBSCs) among which some may chelate heavymetals and thus increase metal accumulation. This study quantifies CBSCs in four epiphytic lichens transplanted for 6months on stands along transects from a highway in southern Norway to search for relationships between concentrations of heavymetals and CBSCs along a gradient in heavymetal pollutants. Viability parameters and concentrations of 21 elements including nutrients and heavymetals in these lichen samples were reported in a separate paper. Medullary CBSCs in fruticose lichens (Ramalina farinacea, Usnea dasypoga) were reduced in the most polluted sites, but not in foliose ones (Parmelia sulcata, Lobaria pulmonaria), whereas cortical CBSC did not change with distance from the road in any species. Strong positive correlations only occurred between the major medullary compound stictic acid present in L. pulmonaria and most heavymetals, consistent with a chelating role of stictic acid, but not of other studied CBSCs or in other species. However, heavymetal chelating did not protect L. pulmonaria against damage because this species experienced the strongest reduction in viability in the polluted sites. CBSCs with an accumulation potential for heavymetals should be quantified in lichen biomonitoring studies of heavymetals because they, like stictic acid, could overshadow pollutant inputs in some species rendering biomonitoring data less useful. In the two fruticose lichen species, CBSCs decreased with increasing heavymetal concentration, probably because heavymetal exposure impaired secondary metabolism. Thus, we found no support for a heavymetal protection role of any CBSCs in studied epiphytic lichens. No intraspecific relationships occurred between CBSCs versus N or C/N-ratio. Interspecifically, medullary CBSCs decreased and cortical CBSCs increased with increasing C/N-ratio. PMID:26437350

Heavymetals in drinking water pose a threat to human health. Populations are exposed to heavymetals primarily through water consumption, but few heavymetals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavymetals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavymetals, mainly due to their limited economic capacities to use advanced technologies for heavymetal removal. This paper aims to review the state of research on heavymetals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavymetals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavymetals in drinking water. PMID:27355520

An empirical equation was developed to quantitatively describe heavymetal sorption in ternary systems of lead (Pb), copper (Cu) and cadmium (Cd). The three sorbants investigated were bentonite, forest soil and spruce bark. This multi-sorption equation is based on three assumptions: the relationship between sorption and initial heavymetal concentration fits a power curve; the presence of one heavymetal proportionately reduces the sorption curve of another heavymetal; and the competition between two heavymetals is independent of the presence of other heavymetals. The multi-sorption equation modeled sorption in ternary systems to a regression fit greater than 0.96. The data required for the equation were generated from a technically straightforward and quick laboratory program involving batch adsorption tests. PMID:14977144

To study the distribution of heavymetals in outdoor settled dusts in different functional areas, based on the literature published, we described the difference in heavymetal accumulation in functional areas and their sources by comparing and analyzing the data of heavymetal concentrations in some capital cities. The results showed that industrial area had the highest heavymetal concentration, followed in descending order by residential area and commercial area, and finally, traffic area. The levels of Zn and Pb in the four functional areas showed higher spatial variability, while there was little difference in Cu and Cd levels. Compared to the heavymetal concentration in urban soils, industrial area appeared heavily accumulated and traffic area appeared lighter accumulated with heavymetals, while there was little difference among other three functional areas expect industrial area. The accumulation of Cd in the four functional areas showed the lowest spatial variability. PMID:24289018

The heavymetal inventory and the ecological risk of the tidal flat sediments in Haizhou Bay were investigated. Results show that the average concentrations of heavymetals in the surface sediments exceeded the environment background values of Jiangsu Province coastal soil, suggesting that the surface sediments were mainly polluted by heavymetals (Cd, Cr, Cu, Mn, Pb and Zn). In addition, the profiles of heavymetals fluxes can reflect the socio-economic development of Lianyungang City, and heavymetals inputs were attributed to anthropogenic activities. Cr, Cu, Pb and Zn were mainly present in the non-bioavailable residual form in surface sediments, whereas Cd and Mn were predominantly in the highly mobile acid soluble and reducible fractions. The ecological risk of the polluted sediments stemmed mainly from Cd and Pb. According to the Sediment quality guidelines (SQGs), however, the adverse biological effects caused by the heavymetals occasionally occurred in tidal flat. PMID:23820195

The heavymetal content of several rubbish bags used to collect the organic fraction of municipal solid waste (OFMSW) is shown in this paper. Nowadays, several public awareness campaigns carried out by municipalities have promoted rubbish bags based mainly on their appearance, without concern for their heavymetal content. A high amount of heavymetals was detected in some polyethylene bags promoted in different campaigns for OFMSW source-sorted collection, while compostable bags presented low quantities of heavymetals. Some other rubbish bags, as well as commercial bags, were also analysed for comparison. These results should be taken into account before promoting the use of one or other type of bag. Moreover, the rubbish bag manufacturers should reduce the heavymetal content in order to avoid heavymetal scattering in the environment, and also to reduce the consumption of raw materials. PMID:20400284

A study was completed to characterize the concentrations of heavymetals and radionuclides and their mobility in two fly ash covered parking lots at the US Department of Energy`s Pantex Plant. Six composite samples collected from the parking areas were analyzed by an offsite contract laboratory for arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, uranium 234, and uranium 238. All metal and radionuclide concentrations except mercury and silver exceeded the applicable comparison standards for typical Pantex Plant soil; however, concentrations of mercury and silver were significantly below the Texas Risk Reduction Standards. In view of these results, it was strongly recommended that fly ash not be used for future projects at the Pantex Plant unless specialized engineering controls are used.

The removal of heavymetal ions by dried aquatic macrophytes was investigated. The ability of the biomass, Eichhornia crassipes (water hyacinth), Typha latifolia (cattail), Sparganium minimum (burr reed) and Menyanthes trifoliata to abstract lead and mercury ions is presented here, along with a conceptual filter design. This paper examines an alternative to both the traditional and recent systems designed for metal removal. It involves the use of dried aquatic macrophytes. There are numerous advantages for the use of dried macrophytes in the treatment of industrial wastewater. First, it is cost-effective. There are also funding opportunities through a variety of Environmental Protection Agency`s (EPA) programs. It is more environmentally conscious because a wetland, the harvesting pond, has been created. And, it creates public goodwill by providing a more appealing, less hardware-intensive, natural system.

Increasing heavymetal contamination of soil and water has produced a need for economical and effective methods to reduce toxic buildup of these materials. Biological systems use metallothionein proteins to sequester such metals as Cu, Cd, and Zn. Studies are underway to genetically engineer a cyanobacteria strain with increased ability for metallothionein production and increased sequestration capacity. Cyanobacteria require only sunlight and CO{sub 2}. Vector constructs are being developed in a naturally competent, unicellular cyanobacterium Anacystis nidulans R2. Closed copies of a yeast copper metallothionein gene have been inserted into a cyanobacterial shuttle vector as well as a vector designed for genomic integration. Transformation studies have produced recombinant cyanobacteria from both of these systems, and work is currently underway to assess the organism`s ability to withstand increasing Cu, Cd, and Zn concentrations.

Biosorption of heavymetals by various biological materials has been studied extensively in the last decade due to its potential particularly in wastewater treatment. The presence of a large number of metals in industrial metal-bearing solutions makes it necessary to investigate their effect on the final metal uptake by individual biosorbent materials. Nonliving biomass of Sargassum, a brown marine alga, is capable of binding more than 10% of its dry weight in toxic cadmium ions. Although ubiquitous iron interferes with Cd uptake, only approximately 4.5% of it is sequestered (biomass dry weight). Biosorption of both metals at pH 4.5 could be described by Langmuir-type isotherms with b, the affinity-related coefficient (Cd: b = 0.015; Fe: b = 0.027). The interference of Fe with Cd uptake, and vice versa, was assessed by deriving three-dimensional equilibrium two-metal sorption isotherm surfaces, smoothed and cut to reveal the inhibition effect of Fe on biosorption of Cd: at the equilibrium concentration Cf[Cd] = 1.5 mM, the presence of Fe at 1.5 mM equilibrium concentration suppressed the Cd uptake to only 76% of the original value. For 50% Cd uptake reduction, a very high equilibrium Fe presence of 4.5 mM was required. The Cd presence affected the uptake of Fe very strongly. To obtain equal values of uptake for each metal in the biosorbent, the ratio of equilibrium concentrations of 0.42 Cd to 1 Fe is necessary in the liquid phase.

The Department of Energy (DOE) established the Office of Technology Development (EM-50) (OTD) as an element of Environmental Restoration and Waste Management (EM) in November, 1989. OTD has begun to search out, develop, test and demonstrate technologies that can now or in the future be applied to the enormous remediation problem now facing the DOE and the United States public in general. Technology demonstration projects have been designed to attack a separate problem as defined by DOE. The HeavyMetals Contaminated Soil Project was conceived to test and demonstrate off-the-shelf technologies (dominantly from the mining industry) that can be brought to bear on the problem of radionuclide and heavymetal contamination in soils and sediments. The Resource Recovery Project is tasked with identifying, developing, testing, and evaluating new and innovative technologies for the remediation of metal contaminated surface and groundwater. An innovative twist on this project is the stated goal of recovering the metals, formerly disposed of as a waste, for reuse and resale, thereby transforming them into a usable resource. Finally, the Dynamic Underground Stripping Project was developed to demonstrate and remediate underground spills of hydrocarbons from formations that are (1) too deep for excavation, and/or (2) require in-situ remediation efforts of long duration. This project has already been shown effective in reducing the time for remediation by conventional methods from an estimated 200 years at the Lawrence Livermore National Laboratory (LLNL) to less than one year. The savings in time and dollars from this technology alone can be immeasurable.

Levels of contaminants in fish are of particular interest because of the potential risk to humans who consume them. While attention has focused on self-caught fish, most of the fish eaten by the American public comes from commercial sources. We sampled 11 types of fish and shellfish obtained from supermarkets and specialty fish markets in New Jersey and analyzed them for arsenic, cadmium, chromium, lead, manganese, mercury, and selenium. We test the null hypothesis that metal levels do not vary among fish types, and we consider whether the levels of any metals could harm the fish themselves or their predators or pose a health risk for human consumers. There were significant interspecific differences for all metals, and no fish types had the highest levels of more than two metals. There were few significant correlations (Kendall tau) among metals for the three most numerous fish (yellowfin tuna, bluefish, and flounder), the correlations were generally low (below 0.40), and many correlations were negative. Only manganese and lead positively were correlated for tuna, bluefish, and flounder. The levels of most metals were below those known to cause adverse effects in the fish themselves. However, the levels of arsenic, lead, mercury, and selenium in some fish were in the range known to cause some sublethal effects in sensitive predatory birds and mammals and in some fish exceeded health-based standards. The greatest risk from different metals resided in different fish; the species of fish with the highest levels of a given metal sometimes exceeded the human health guidance or standards for that metal. Thus, the risk information given to the public (mainly about mercury) does not present a complete picture. The potential of harm from other metals suggests that people not only should eat smaller quantities of fish known to accumulate mercury but also should eat a diversity of fish to avoid consuming unhealthy quantities of other heavymetals. However, consumers should

An electrorefiner system according to a non-limiting embodiment of the present invention may include a vessel configured to maintain a molten salt electrolyte and configured to receive a plurality of alternately arranged cathode and anode assemblies. The anode assemblies are configured to hold an impure nuclear feed material. Upon application of the power system, the impure nuclear feed material is anodically dissolved and a purified metal is deposited on the cathode rods of the cathode assemblies. A scraper is configured to dislodge the purified metal deposited on the cathode rods. A conveyor system is disposed at a bottom of the vessel and configured to remove the dislodged purified metal from the vessel.

Copper, iron, manganese and zinc are four essential elements for plant growth. Mapping heavymetal migration and distribution in soils is a preliminary step in assessing heavymetal availability in soils. However, data of qualitative and quantitative trace elements composition of soils of Argentina are scarce. Despite the small amounts required by plants, agricultural soils are usually deficient in one or more micronutrients, therefore, their concentration in plant tissues falls below the levels that allow optimal growth. Soil nature plays a fundamental role in the availability of micronutrients and their behaviour at a soil-plant level. The aim of this study is to determine the plant availability and areas of deficiency in agricultural soils with risk of salinization. The presented maps have been elaborated on the basis of the information provided by the monochromatic aerial photographs, scale 1:7000 and projected using the topographic information of the National Topographic Maps. Soils were sampled according to the spatial variation of soil types and land use. Sampling points were geo-referenced. Soil samples were analyzed at the laboratory for complete physicochemical and mineralogical characteristics. The percentage of organic matter is the determining factor in the presence and distribution of the available metals in the soils of the studied area, being the top horizon the one of greatest accumulation. CuDTPA, FeDPTA and MnDPTA are mobile within the profile, whereas ZnDPTA remains adsorbed without vertical displacement. ZnDTPA is the only available metal which also shows differences due to soil salinity and textural classes. However, soil geochemical conditions imply low extractability and a certain difficulty for micronutrient absorption by plants.

Hypolimnetic aeration (a form of artificial aeration) has gained popularity in recent years as a lake restoration and management tool. The addition of oxygen to eutrophic lakes by hypolimnetic aeration has been shown to increase overall water quality, without disturbing thermal stratification. The effects of increasing dissolved oxygen levels by aeration on the chemistry of heavymetals in lakes where the sediments are contaminated and the possible repercussions, however, have yet to be investigated. In this laboratory study, sediments collected from a lake contaminated with metal-sulfides were exposed to various levels of dissolved oxygen in the overyling water column. concentrations of zinc, cadmium, and lead in the water column were shown to increase concomitantly with increasing concentrations of sulfate in the water as aeration progressed. The effects of varying concentrations of dissolved oxygen, as well as other factors effecting the availability of previously insoluble heavymetals will be discussed.

A fundamentally new working principle into the field of self-powered heavy-metal-ion detection and removal using the triboelectrification effect is introduced. The as-developed tribo-nanosensors can selectively detect common heavymetal ions. The water-driven triboelectric nanogenerator is taken as a sustainable power source for heavy-metal-ion removal by recycling the kinetic energy from flowing wastewater. PMID:26913810

Condensed matter physics is an area of research which lies at a sweet spot between two complementary perspectives: the atomistic point of view which takes into account all the details of the system of interest; and the framework of universality and emergent phenomena, which allows us to make drastic simplifications to the microscopic description of materials while still being able to explain much of the experimentally observed phenomena. This thesis addresses problems from both perspectives, focusing on heavy fermion systems. Heavy fermion systems are prototype materials for the study of strongly correlations and quantum criticality. Theoretical understanding of these systems is important for the design of new materials and for the fundamental understanding of quantum critical phenomena. This thesis is strongly motivated by recent experiments in an intrinsically quantum critical material, beta-YbAlB 4. This system shows anomalous critical exponents in transport and thermodynamics. In Chapter 2 we construct a phenomenological theory for the heavy fermion metal beta-YbAlB4 based on the Anderson model, taking into account the peculiarities of this specific material. We analyze the consequences of a non-trivial, momentum-dependent, hybridization matrix between f-electrons and conduction electrons, which gives rise to a nodal metal with unusual dispersion and singular thermodynamic properties, in accordance with experiments. In Chapter 3 we analyze the Electron Spin Resonance experiments in this same material and propose a theory including spin-orbit coupling, crystal electric fields and hyperfine coupling which can account for many of the features of the experimentally observed signal. Within a broader perspective on heavy fermion systems, the absence of a single unified theoretical description which can account for the plethora of phenomena observed in this class of materials also motivates us to consider new theoretical approaches. In Chapter 4 we generalize the

To solve the trace metal pollution of a Pd/Zn mine in Hunan province, a greenhouse pot experiment was conducted to investigate the effect of two arbuscular mycorrhizal fungi, Glomus mosseae (Gm) and Glomus intraradices (Gi), on the growth, heavymetal uptake and accumulation of Zenia insignis Chun, the pioneer plant there. The results showed that symbiotic associations were successfully established between the two isolates and Z. insignis in heavymetal contaminated soil. AM fungi improved P absorption, biomass and changed heavymetal uptake and distribution of Z. insignis. AM fungi-inoculated plants had significantly lower Fe, Cu, Zn, Pd concentrations and higher Fe, Cu, Zn, Pd accumulation than non-inoculated plants. However, Gm and Gi showed different mycorrhizal effects on the distribution of heavymetal in hosts, depending on the species of heavymetal. Gi-inoculated Z. insignis showed significantly lower TF values of Fe, Zn, Pd than Gm and non-inoculated plants, while both strains had no effect on TF value of Cu, which indicated that Gi enhanced trace metal accumulation in root system, playing a filtering/sequestering role in the presence of trace metals. The overall results demonstrated that AM fungi had positive effect on Z. insignis in enhancing the ability to adapt the heavymetal contaminated soil and played potential role in the revegetation of heavymetal contaminated soil. But in practical application, the combination of AM, hosts and heavymetal should be considered. PMID:25338391

Concentrations of six heavymetals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavymetals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavymetals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavymetals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavymetals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavymetals after its propagule stage for its regeneration and growth to be significantly affected by heavymetal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavymetals in an ecosystem. PMID:23203819

We report an economical and eco-friendly way to remove the heavymetal pollutant using modified clay. The modification of clay was done by calcining the natural clay from Kyushu region in Japan. Further, the removal efficiency for various pH and contact time was evaluated. The morphology of the clays was studied using the scanning electron microscopy (SEM). The structural and chemical analyses of modified clay were done by using X-ray diffraction (XRD), Raman spectroscopy, and Energy dispersion analysis (EDAX) to understand the properties related to the removal of heavymetal pollutant. Further, we studied the absorption efficiency of clay for various pH and contacting time using Ni polluted water. The modified clays show better removal efficiency for all pH with different saturation time. The adsorption follows pseudo-second order kinetics and the adsorption capacity of modified clay is 1.5 times larger than that of natural clay. The increase in the adsorption efficiency of modified clay was correlated to the increase in hematite phase along with increase in surface area due to surface morphological changes. PMID:27483775

Surface and subsurface contamination of soils by heavymetals, including Pb, Cr, Cu, Zn, and Cd has become an area of concern for many industrial and government organizations (1) Conventional sampling and analysis techniques for soil provide a high degree of sensitivity and selectivity for individual analytes. However, obtaining a representative sampling and analysis from a particular site using conventional techniques is time consuming and costly (2) Additionally, conventional methods are difficult to implement in the field for in situ and/or real-time applications. Therefore, there is a need for characterization and monitoring techniques for heavymetals in soils that allow cost-effective, rapid, in situ measurements. The overall objectives of this project are to evaluate potential calibration techniques for the laser-induced breakdown spectroscopy (LIBS)-CPT instrument, to provide a preliminary evaluation of the LIBS instrument calibration using samples obtained from the field and to provide technical support to field demonstration of the LIBS-CPT instrument at a DOE facility.

Metabolic engineering approaches are increasingly employed for environmental applications. Because phytochelatins (PC) protect plants from heavymetal toxicity, strategies directed at manipulating the biosynthesis of these peptides hold promise for the remediation of soils and groundwaters contaminated with heavymetals. Directed evolution of Arabidopsis thaliana phytochelatin synthase (AtPCS1) yields mutants that confer levels of cadmium tolerance and accumulation greater than expression of the wild-type enzyme in Saccharomyces cerevisiae, Arabidopsis, or Brassica juncea. Surprisingly, the AtPCS1 mutants that enhance cadmium tolerance and accumulation are catalytically less efficient than wild-type enzyme. Metabolite analyses indicate that transformation with AtPCS1, but not with the mutant variants, decreases the levels of the PC precursors, glutathione and γ-glutamylcysteine, upon exposure to cadmium. Selection of AtPCS1 variants with diminished catalytic activity alleviates depletion of these metabolites, which maintains redox homeostasis while supporting PC synthesis during cadmium exposure. These results emphasize the importance of metabolic context for pathway engineering and broaden the range of tools available for environmental remediation. PMID:26018077

Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavymetals from fly ashes through the electrodialytic process (EDR) has been tried out before. The goal of removing heavymetals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even consider application to the soil. ST ash is the only residue that gets concentrations low enough to be reused, but its fertilizing value might be questioned. An alternative reuse for the three ashes is here preliminary tested, the combination of fly ash with mortar. Fly ashes have been substituted by cement fraction or aggregate fraction. Surprisingly, better compressive strengths were obtained by replacing the aggregate fraction. CW ashes presented promising results for the substitution of aggregate in mortar and possibly in concrete. PMID:21167631

Metabolic engineering approaches are increasingly employed for environmental applications. Because phytochelatins (PC) protect plants from heavymetal toxicity, strategies directed at manipulating the biosynthesis of these peptides hold promise for the remediation of soils and groundwaters contaminated with heavymetals. Directed evolution of Arabidopsis thaliana phytochelatin synthase (AtPCS1) yields mutants that confer levels of cadmium tolerance and accumulation greater than expression of the wild-type enzyme in Saccharomyces cerevisiae, Arabidopsis, or Brassica juncea. Surprisingly, the AtPCS1 mutants that enhance cadmium tolerance and accumulation are catalytically less efficient than wild-type enzyme. Metabolite analyses indicate that transformation with AtPCS1, but not with the mutant variants, decreases the levels of the PC precursors, glutathione and γ-glutamylcysteine, upon exposure to cadmium. Selection of AtPCS1 variants with diminished catalytic activity alleviates depletion of these metabolites, which maintains redox homeostasis while supporting PC synthesis during cadmium exposure. These results emphasize the importance of metabolic context for pathway engineering and broaden the range of tools available for environmental remediation. PMID:26018077

A series of geopolymers were synthesized by mixing metakaolinite, water glass, sodium hydroxide and water, and the lead ion solidification experiments were performed with the geopolymer. Then, the immobilization efficiency was characterized by monitoring the leaching concentration and compressive strength of solidified products. Additionally, the structure and properties of the solidified products were studied by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of immobilization efficiency, microstructure and mineral structure, the difference between geopolymer and cement on the performance of immobilizing heavymetals was discussed. The results of lead ion immobilization experiments showed that over 99.7% of heavymetal was captured by the geopolymer as the doping concentration of lead ion was less than 3%. Meanwhile, the compressive strength of the solidified product ranged from 40 MPa to 50 MPa. Furthermore, by using the same Pb2+ concentration, the geopolymer showed higher compressive strength and lower leaching concentration compared to the cement. Because lead ion participated in constitution of structure of geopolymer, or Pb2+ was adsorbed by the aluminium ions on the geopolymeric skeleton and held in geopolymer. However, cement mainly solidified lead ion by physical encapsulation and adsorption mechanism. Therefore, both from the compressive strength and leaching concentration and from the microstructure characterization as well as the mechanism of the geopolymerization reaction, the geopolymer has more advantages in immobilizing Pb2+ than the cement. PMID:21780604

Recently, in Brazil, it has appeared a new and unusual "plague" in lazer and commercial fishing. It is caused by the parasitic larval phase of certain native bivalve mollusks of fresh water known as "Naiades" and its involves the presence of big bivalve of fresh water, mainly Anodontites trapesialis, in the tanks and dams of the fish creation. These bivalve mollusks belong to the Unionoida Order, Mycetopodidae Family. The objective of the present work was to analyze the shells of these mollusks to verify the possibility of use as bioindicators for heavymetals in freshwater. The mollusks shells were collected in a commercial fishing at Londrina-PR. A qualitative analysis was made to determine the chemical composition of the shells and verify a possible correlation with existent heavymetals in the aquatic environment. In the inner part of the shells were identified the elements Ca, P, Fe, Mn and Sr and in the outer part were identified Ca, P, Fe, Mn, Sr and Cu. The Ca ratio of the outer part by inner part of the analyzed shells is around of 1, as expected, because Ca is the main compound of mollusks shells. The ratio of P, Fe, Mn, and Sr to the Ca were constant in all analyzed shells, being close to 0.015. The ratio Cu/Ca varied among the shells, showing that this mollusk is sensitive to concentration of this element in the aquatic environment.

Concentrations of 14 heavymetals (Ag, As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Tl, V, and Zn) in needles, twigs, bark and xylem of spruce and fir collected at the timberline of eight sites along the Hengduan Mountains, eastern Tibetan Plateau, are reported. Twigs had the highest concentration for most of elements, while xylem had the lowest concentration. The connections between elements in twigs were much richer than other organ/tissues. Pb, Ni, As, Sb, Co, Cd, Hg, Cr and Tl which are partly through anthropogenic sources and brought in by monsoon, have been accumulated in twigs and needles by wet or dry deposition in south and east sites where are within or near pollutant sources. Under moderate pollution situation, vegetation are able to adjust the nutrient element (Cu and Zn) cycle rate, thus maintain a stable concentration level. Seldom V, Ag, and Mo are from external anthropogenic sources. Needles and twigs can be used as biomonitors for ecosystem environment when needles can simply distinguish the origin of elements and twigs are more sensitive to extra heavymetal input. PMID:24817526

The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavymetal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavymetal-contaminated soil could be remediated with a combination of chemical treatments and plants. PMID:10819205

All the data and features of properties of heavy-electron systems mentioned in this presentation represent only a fraction of recent results obtained in this field. Nevertheless they should demonstrate that interesting physics may be explored in studies of these materials. Most results that are obtained are important with regard to the understanding of metals in general. These substances are suited for studies of all aspects of many-body effects among conduction electrons in metals and are an important link to quantum fluids or solids like {sup 3}He. The quite well established occurrence of unconventional superconductivity is among the most prominent features of heavy-electron physics and, also here, provides a merging of interest with another hot topic of condensed-matter physics, the phenomenon of superconductivity in oxides at relatively high temperatures and in organic substances. As a final comment the author recalls the importance of the materials-science aspects in these problems. The demonstrated strong influence of small amounts of impurities or imperfections on the physical properties of these substances certainly deserves further attention in future experimental and theoretical work.

The genotoxic properties of soils polluted with heavymetals were studied on two wayside slopes covered with trees in the city of Voronezh. The nucleolar test in cells of the apical meristem of Zebrina pendula Schnizl. roots was used. The genotoxic effect of the soils was revealed according to the increased number of 2-and 3-nucleolar cells (from 41 to 54% and from 19 to 23% in the upper part of the first and second slopes, respectively; in the control, their number was 18 and 7%). The mean number of nucleoli per cell increased from 1.7 to 1.95 in the experiment and 1.31 in the control. The increased vehicle emissions, especially when cars go up the slopes (mainly in the upper and middle parts), correlated with the elevated heavymetal (Pb, Cu, Cd, and Zn) contents in the soil. The mutagenic substances may be removed to the Voronezh Reservoir, where they may be accumulated in some living organisms.

Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavymetals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease. PMID:23690738

Fe, Ni, and V are considered trace impurities in heavy crude oils and tar sand bitumens. In order to understand the importance of these metals, we have examined several properties: (1) bulk metals levels, (2) distribution in separated fractions, (3) size behavior in feeds and during processing, (4) speciation as a function of size, and (5) correlations with rheological properties. Some of the results of these studies show: (1) V and Ni have roughly bimodal size distributions, (2) groupings were seen based on location, size distribution, and Ni/V ratio of the sample, (3) Fe profiles are distinctively different, having a unimodal distribution with a maximum at relatively large molecular size, (4) Fe concentrations in the tar sand bitumens suggest possible fines solubilization in some cases, (5) SARA separated fractions show possible correlations of metals with asphaltene properties suggesting secondary and tertiary structure interactions, and (6) ICP-MS examination for soluble ultra-trace metal impurities show the possibility of unexpected elements such as U, Th, Mo, and others at concentrations in the ppB to ppM range. 39 refs., 13 figs., 5 tabs.

Industrial effluent containing heavymetals discharged into streams may pose high toxicity risks to aquatic organisms and to human health. Therefore, it is important to understand how to change the amount of effluent with heavymetals discharged from industries into open aquatic ecosystems both for effective management of heavymetals and to foster sustainable ecosystems. This study was conducted to characterize the release of heavymetals from industries based on the Pollutant Release and Transfer Registers database in Korea from 1999 to 2010. From the database, we selected nine heavymetals (Pb, Cd, Mn, Sb, Cu, Zn, Cr, Sn, and Ni) and compared the differences in their effluent for different types of industries. The heavymetal effluents released into freshwater ecosystems were classified into four clusters through the learning process of the self-organizing map. Cluster 1 was characterized by the relatively higher effluent volumes of heavymetals, whereas cluster 4 had lower effluent volumes. The different patterns of the effluent volumes in heavymetals were closely associated with the differences of industrial types, and the changes of effluents of heavymetals reflected the changes in regulations and laws for aquatic ecosystem management. PMID:24577281

Diplazium esculentum is a widely used medicinal fern in Malaysia and other regions worldwide. Heavymetals in plants should be determined because prolonged human intake of toxic trace elements, even at low doses, results in organ malfunction and causes chronic toxicity. Hence, substantial information should be obtained from plants that grow on soils containing high concentrations of heavymetals. This study aimed to determine the physicochemical characteristics of soil and heavymetal concentrations (Pb, Cr, Mn, Cu, and Zn) in different parts of D. esculentum and soil, which were collected from the fern garden of Universiti Kebangsaan Malaysia. Results showed that heavymetals were highly accumulated in D. esculentum roots.

Populus euphratica is a special kind of woody plant, which lives in desert area of northwestern China and is strongly resistant to multiple abiotic stresses. However, the knowledge about the ecology and physiological roles of microbes associated with P. euphratica is still not enough. In this paper, we isolated 72 strains resistant to heavymetals from rhizospheric soil of wild P. euphratica forest in Shaya County of Xinjiang. There were 50 strains conveying resistance to one of four heavymetals (Cu2+, Ni2+, Pb2+ or Zn2+), and 9 strains were resistant to at least three kinds of these heavymetals. Five of the multi-heavymetal resistant bacteria were inoculated to bamboo willow and the growth inhibition of plant under stresses of Cu2+ or Zn2+ was found to be alleviated to different extent. Among the 5 strains, Pseudomonas sp. Z30 and Cupriavidus sp. N8 significantly improved the growth of plant under stresses of both zinc and copper when compared to the uninoculated controls. The results showed the diversity of heavymetal resistant bacteria associated with P. euphratica which lived in a non-heavymetal polluted area and some of the multi-heavymetal resistant bacteria may greatly improve the growth of host plant under heavymetal.stress. The PGPB associated with P. euphratica has potential application in the xylophyte-microbe remediation of environmental heavymetal pollution. PMID:26785565

Through retaining runoff and pollutants such as heavymetals from surrounding landscapes, ponds around a lake play an important role in mitigating the impacts of human activities on lake ecosystems. In order to determine the potential for heavymetal accumulation of submerged macrophytes, we investigated the concentrations of 10 heavymetals (i.e., As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in water, sediments, and submerged macrophytes collected from 37 ponds around the Dianchi Lake in China. Our results showed that both water and sediments of these ponds were polluted by Pb. Water and sediments heavymetal concentrations in ponds received urban and agricultural runoff were not significantly higher than those in ponds received forest runoff. This result indicates that a large portion of heavymetals in these ponds may originate from atmospheric deposition and weathering of background soils. Positive relationships were found among heavymetal concentrations in submerged macrophytes, probably due to the coaccumulation of heavymetals. For most heavymetals, no significant relationships were found between submerged macrophytes and their water and sediment environments. The maximum concentrations of Cr, Fe and Ni in Ceratophyllum demersum were 4242, 16,429 and 2662mgkg(-1), respectively. The result suggests that C. demersum is a good candidate species for removing heavymetals from polluted aquatic environments. PMID:25011115

Concentrations of heavymetals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in Pleurozium schreberi (Brid.) Mitt., a common moss species, were used to indicate relative levels of atmospheric deposition in Poland in the years 1975-1998. Spatial and temporal differences in the heavymetal concentrations in mosses were found. The highest concentration of heavymetals was recorded in the moss samples from the southern, most industrialised part of the country, and the lowest from north-eastern Poland. A significant decrease of heavymetals over 20 years (1975-1998) was found. PMID:11584642

Industrial effluent containing heavymetals discharged into streams may pose high toxicity risks to aquatic organisms and to human health. Therefore, it is important to understand how to change the amount of effluent with heavymetals discharged from industries into open aquatic ecosystems both for effective management of heavymetals and to foster sustainable ecosystems. This study was conducted to characterize the release of heavymetals from industries based on the Pollutant Release and Transfer Registers database in Korea from 1999 to 2010. From the database, we selected nine heavymetals (Pb, Cd, Mn, Sb, Cu, Zn, Cr, Sn, and Ni) and compared the differences in their effluent for different types of industries. The heavymetal effluents released into freshwater ecosystems were classified into four clusters through the learning process of the self-organizing map. Cluster 1 was characterized by the relatively higher effluent volumes of heavymetals, whereas cluster 4 had lower effluent volumes. The different patterns of the effluent volumes in heavymetals were closely associated with the differences of industrial types, and the changes of effluents of heavymetals reflected the changes in regulations and laws for aquatic ecosystem management. PMID:24577281

The concentrations of cadmium, copper, lead, manganese, and zinc were determined in the hair of 40 pet dogs of both sexes. Of the heavymetals, zinc showed the highest concentration in the hair regardless of sex or color. Zinc also increased gradually with age. Cadmium and lead increased in concentration up to 7 years of age and decreased thereafter. Correlations were made among the heavymetal concentrations in the hair. Comparisons also were made with available human data. It was suggested that analysis of heavymetals in the hair of house-dogs may be valuable as a means of biological monitoring of the human heavymetal body burden. (RJC)

Urban roadside soils are important environmental media for assessing heavymetal concentrations in urban environment. However, among other things, heavymetal concentrations are controlled by soil particle grain size fractions. In this study, two roadside sites were chosen within the city of Xuzhou (China) to reflect differences in land use. Bulk soil samples were collected and then divided by particle diameter into five physical size fractions, 500-250, 250-125, 125-74, 74-45, < 45 μm. Concentrations of metals (Ti, Cr, Al, Ga, Pb, Ba, Cd, Co, Cu, Mn, Ni, V, Zn, Mo, As, Sb, Se, Hg, Bi, Ag) were determined for each individual fraction. These metals could be roughly classified into two groups: anthropogenic element (Pb, Ba, Cd, Cu, Zn, Mo, As, Sb, Se, Hg, Bi, Ag) and lithophile element (Ti, Cr, Al, Ga, Co, Mn, Ni, V) in terms of values of enrichment factor. As expected, higher concentrations of anthropogenic heavymetals (Cu, Zn, Mo, As, Hg, Bi, Ag) are observed in the finest particle grain size fraction (i.e. < 45 μm). However, heavymetals Se, Sb and Ba behave independently of selected grain size fractions. From the viewpoint of mass loading, more than 30% of the concentrations for all anthropogenic heavymetals are contributed by the particle grain size fractions of 45-74 μm at site 1 and more than 70% of the concentrations for all heavymetals are contributed by the particle grain size fractions of 45-74 and 74-125 μm at site 2. These results are important for transport of soil-bound heavymetals and pollution control by various remedial options.

Highlights: Black-Right-Pointing-Pointer Sentences/phrases were modified. Black-Right-Pointing-Pointer Necessary discussions for different figures were included. Black-Right-Pointing-Pointer More discussion have been included on the flue gas analysis. Black-Right-Pointing-Pointer Queries to both the reviewers have been given. - Abstract: The global crisis of the hazardous electronic waste (E-waste) is on the rise due to increasing usage and disposal of electronic devices. A process was developed to treat E-waste in an environmentally benign process. The process consisted of thermal plasma treatment followed by recovery of metal values through mineral acid leaching. In the thermal process, the E-waste was melted to recover the metal values as a metallic mixture. The metallic mixture was subjected to acid leaching in presence of depolarizer. The leached liquor mainly contained copper as the other elements like Al and Fe were mostly in alloy form as per the XRD and phase diagram studies. Response surface model was used to optimize the conditions for leaching. More than 90% leaching efficiency at room temperature was observed for Cu, Ni and Co with HCl as the solvent, whereas Fe and Al showed less than 40% efficiency.

Products of the reaction between dialdehyde starch and Y-NH2 compounds (e.g. semicarbazide or hydrazine) are effective ligands for metal ions. The usefulness of these derivatives was tested in the experiment, both in terms of the immobilization of heavymetal ions in soil and the potential application in phytoextraction processes. The experimental model comprised maize and the ions of such metals as: Zn(II), Pb(II), Cu(II), Cd(II), and Ni(II). The amount of maize yield, as well as heavymetal content and uptake by the aboveground parts and roots of maize, were studied during a three-year pot experiment. The results of the study indicate the significant impact of heavymetals on reduced yield and increased heavymetal content in maize. Soil-applied dialdehyde starch derivatives resulted in lower yields, particularly disemicarbazone (DASS), but in heavymetal-contaminated soils they largely limited the negative impact of these metals both on yielding and heavymetal content in plants, particularly dihydrazone (DASH). It was demonstrated that the application of dihydrazone (DASH) to a soil polluted with heavymetals boosted the uptake of Zn, Pb, Cu, and Cd from the soil, hence there is a possibility to use this compound in the phytoextraction of these metals from the soil. Decreased Ni uptake was also determined, hence the possibility of using this compound in the immobilization of this metal. The study showed that dialdehyde starch disemicarbazone was ineffective in the discussed processes. PMID:26280197

A Pb and Zn separation method from salts (Na, K, and Cl) in a simulated multicomponent gas generated by the incineration fly ash melting is studied. The heavymetals are separated using a two-stage dust collection technique. A standard reagents mixture is volatilized by heating in a lab-scale reactor to generate the simulated multicomponent gas. The volatilized salts in the gas are condensed and collected by a filter at a high temperature (600-800 °C), allowing Pb and Zn to pass through the filter as gaseous species. The gaseous heavymetals are condensed by lowering their temperature to 100 °C and collected. The metal separation is promoted by elevating the temperature used in the first-stage dust collection to 800 °C and maintaining a reductive atmosphere in the reactor. Subsequently, a sequential chemical extraction is performed on the obtained materials to evaluate the metals leaching characteristics from the materials. In the separated salts to be landfilled, a portion of toxic metals such as Pb, Cd, As, and Cr remain as water-soluble compounds. The separated Pb and Zn, to be extracted and recovered with precipitation for the metal enrichment, can be extracted using water, acid (pH 3), or CH₃COONH₄ solution (1M). PMID:23611806

A dual zone chemical reactor continuously processes metal-containing materials while regenerating and circulating a liquid carrier. The starting materials are fed into a first reaction zone of a vessel containing a molten salt carrier. The starting materials react to form a metal product and a by-product that dissolves in the molten salt that flows to a second reaction zone in the reaction vessel. The second reaction zone is partitioned from, but in fluid communication with, the first reaction zone. The liquid carrier continuously circulates along a pathway between the first reaction zone and the second reaction zone. A reactive gas is introduced into the second reaction zone to react with the reaction by-product to generate the molten salt. The metal product, the gaseous waste products, and the excess liquid carrier are removed without interrupting the operation of the reactor. The design of the dual zone reactor can be adapted to combine a plurality of liquid carrier regeneration zones in a multiple dual zone chemical reactor for production scale processing.

A dual zone chemical reactor continuously processes metal-containing materials while regenerating and circulating a liquid carrier. The starting materials are fed into a first reaction zone of a vessel containing a molten salt carrier. The starting materials react to form a metal product and a by-product that dissolves in the molten salt that flows to a second reaction zone in the reaction vessel. The second reaction zone is partitioned from, but in fluid communication with, the first reaction zone. The liquid carrier continuously circulates along a pathway between the first reaction zone and the second reaction zone. A reactive gas is introduced into the second reaction zone to react with the reaction by-product to generate the molten salt. The metal product, the gaseous waste products, and the excess liquid carrier are removed without interrupting the operation of the reactor. The design of the dual zone reactor can be adapted to combine a plurality of liquid carrier regeneration zones in a multiple dual zone chemical reactor for production scale processing. 6 figs.

The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavymetals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavymetals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils. PMID:15046840

To achieve one-step separation of heavymetal ions from contaminated water, we have developed a novel bioremediation technology based on self-immobilization of the Caulobacter crescentus recombinant strain JS4022/p723-6H, which overexpresses hexahistidine peptide on the surface of the bacterial cells and serves as a whole-cell adsorbent for dissolved heavymetals. Biofilms formed by JS4022/p723-6H are effective at retaining cadmium from bacterial growth media or environmental water samples. Here we provide additional experiment data discussing the application potential of this new technology. Supplementation of calcium to the growth media produced robust JS4022/p723-6H cells by alleviating their sensitivity to chelators. After growth in the presence of 0.3% CaCl(2)·2H(2)O, double the amount of JS4022/p723-6H cells survived the treatment with 2 mM EDTA. Free cells of JS4022/p723-6H effectively sequestered 51% of the total cadmium from a Lake Erie water sample at pH 5.4, compared to 37% retrieved by the control strain. Similar levels of adsorption were observed at pH 4.2 as well. Cells of JS4022/p723-6H were tolerant of acid treatment for 90 min at pH ≥1.1 or 120 min at pH ≥2.5, which provides an avenue for the convenient regeneration of the bacterial cells metal-binding capacity with acidic solutions. Designs of possible bioreactors and an operation system are also presented. PMID:21326927

The metropolitan area of the Toluca Valley (MATV) extends over an area of 1208.55 km(2) and has 1,361,500 inhabitants making it the fifth highest populated area in the country and the second highest in the state. The MATV has several environmental problems, with regards to the air quality. Particles PM10 and PM2.5 are considered to be the main pollutant due to these particles frequently exceeding the limit laid down in the standards of the air quality in the country. For this reason, samples of the mosses Fabriona ciliaris and Leskea angustata were collected at different sites in MATV, Mexico in order to establish the atmospheric deposition of heavymetals by means of the analysis of the mosses tissues. Results show the average metal concentrations in the mosses in the order of: Zn > Pb > Cr > Cd. The concentration capacities of heavymetals were higher in Fabriona ciliaris than Leskea angustata. Enrichment factors for Cr, Zn, Pb and Cd were obtained using the soils from the same sampling area. Enrichment factors results show that Cr is conservative in both sampling seasons with a terrigenous origin; Zn is moderately enriched in both sampling seasons and mainly associated to pedological-soil or substrate contribution and anthropogenic activities and Cd is highly enriched in the rainy season and Pb is highly enriched in both sampling seasons, with a predominantly anthropogenic origin. This study provides information to be considered in the strategies for similar environmental problems in the world. PMID:27375984

Anniston, Alabama has a long history of operation of foundries and other heavy industry. We assessed the extent of heavymetal contamination in soils by determining the concentrations of 11 heavymetals (Pb, As, Cd, Cr, Co, Cu, Mn, Hg, Ni, V, and Zn) based on 2046 soil samples collected from 595 industrial and residential sites. Principal Component Analysis (PCA) was adopted to characterize the distribution of heavymetals in soil in this region. In addition, a geostatistical technique (kriging) was used to create regional distribution maps for the interpolation of nonpoint sources of heavymetal contamination using geographical information system (GIS) techniques. There were significant differences found between sampling zones in the concentrations of heavymetals, with the exception of the levels of Ni. Three main components explaining the heavymetal variability in soils were identified. The results suggest that Pb, Cd, Cu, and Zn were associated with anthropogenic activities, such as the operations of some foundries and major railroads, which released these heavymetals, whereas the presence of Co, Mn, and V were controlled by natural sources, such as soil texture, pedogenesis, and soil hydrology. In general terms, the soil levels of heavymetals analyzed in this study were higher than those reported in previous studies in other industrial and residential communities. PMID:24693925

Ferrophos is treated in a plasma furnace by maintaining an electric arc between a cathode and at least one point on the surface of the ferrophos which serves as the anode in the presence of an inert plasma gas, maintaining the average temperature of the ferrophos at about 2,000.degree. C. to about 2,700.degree. C., evolving gaseous phosphorus from the ferrophos until it contains less than about 7% by weight phosphorus, removing a purified phosphorus gas as one product and a metal concentrate having a reduced phosphorus content as a coproduct.

Foam-based adsorbents and a related method of manufacture are provided. The foam-based adsorbents include polymer foam with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the foam-based adsorbents includes irradiating polymer foam, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Foam-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Cadmium (Cd), triethyltin (TET), and trimethyltin (TMT) are heavymetals which are neurotoxic to developing animals. In the present experiment, preweaning assessment of locomotor activity was used to detect and differentiate between the developmental toxicity of these metals. On ...

The feasibility of using dithiocarbamate chelating agents or sulfur-containing organophosphorus reagents for the supercritical fluid extraction (SFE) of toxic heavymetals from solid and aqueous matrices is investigated. Effective extraction of heavymetal ions from both sand matrix and water samples was demonstrated by using supercritical CO2 containing dithiocarbamatechelating agents. A commercially available sulfur-containing organophosphorus reagent, Cyanex 302, was used for the extraction of toxic heavymetals from wood samples. The extraction profiles were initially rapid followed by a very low level of metal extraction, indicating that the process is limited to extraction of leachable toxic metals.

A heavymetal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavymetal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavymetals on the spent FCC catalyst as an intermediate step.

A heavymetal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavymetal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavymetals on the spent FCC catalyst as an intermediate step.

Trace heavymetals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavymetals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavymetal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavymetal contamination in several areas of Pakistan over the past few years, particularly to assess the heavymetal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

Trace heavymetals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavymetals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavymetal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavymetal contamination in several areas of Pakistan over the past few years, particularly to assess the heavymetal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

Arbuscular mycorrhizal fungi (AMF) are important components of soil microbial communities, and play important role in plant growth. However, the effects of AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) on host plant under various heavymetal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) and host plant functional groups (herbs vs. trees, and non-legumes vs. legumes) at three heavymetal levels. In the meta-analysis, we calculate the effect size (ln(RR)) by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavymetal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavymetal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavymetal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavymetal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavymetal levels. Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavymetal level, while trees and legumes grew better than herbs and non-legumes did under medium heavymetal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavymetal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavymetal polluted environment. PMID:25288547

Comparative leaching experiments were carried out using leaching medium with different pH to municipal solid waste in the landfill columns in order to investigate the mobility of heavymetals. The leachate pH and oxidation-reduction potential were measured by oxidation-reduction potential analyzer; the contents of heavymetals were measured by inductively coupled plasma mass spectrometry. It is very different in leaching concentrations of heavymetals; the dynamic leaching of heavymetals decreased with the rise of the leaching amount on the whole. Acid leaching medium had definite influence on the leaching of heavymetals in the early landfill, but it had the obvious inhibition effect on the leaching in the middle and late period of landfill; the neutral and alkaline leaching medium are more beneficial to the leaching of heavymetals. Due to the influence of the environment of landfill, the differences of the results in cumulative leaching amount, leaching rate, and leaching intensity of heavymetals are very big. The calculation results of the release rates of heavymetals prove that the orders of the release rates are not identical under different leaching conditions. Acid rain made heavymetals migrate from municipal solid waste to soil and detain in soil more easily; approached neutral and alkaline leaching mediums are more beneficial to leaching of heavymetals in the municipal solid waste and soil with leachate. The field verification of experimental data showed that the law of heavymetal leaching in municipal solid waste revealed by the experiment has a good consistency with the data obtained by municipal solid waste landfill. PMID:19466573

In order to understand the pollution characteristics of heavymetals in surface water sediments of Yongkang, we analyzed the concentrations of 10 heavymetals including Ti, Cr, Mn, Co, Ni, Cu, Zn, As, Pb and Fe in 122 sediment samples, explored the underlying source of heavymetals and then assessed the potential ecological risks of those metals by methods of the index of geo-accumulation and the potential ecological risk. The study results showed that: 10 heavymetal contents followed the order: Fe > Ti > Mn > Zn > Cr > Cu > Ph > Ni > As > Co, all heavymetals except for Ti were 1. 17 to 3.78 times higher than those of Zhejiang Jinhua- Quzhou basin natural soils background values; The concentrations of all heavymetals had a significantly correlation between each other, indicating that those heavymetals had similar sources of pollution, and it mainly came from industrial and vehicle pollutions; The pollution extent of heavymetals in sediments by geo-accumulation index (Igeo) followed the order: Cr > Zn > Ni > Cu > Fe > As > Pb >Mn > Ti, thereinto, Cr, Zn, Cu and Ni were moderately polluted or heavily polluted at some sampling sites; The potential ecological risk of 9 heavymetals in sediments were in the following order: Cu > As > Ni > Cr > Pb > Co > Zn > Mn > Ti, Cu and As contributed the most to the total potential ecological risk, accounting for 22.84% and 21. 62% , others had a total of 55.54% , through the ecological risk assessment, 89. 34% of the potential ecological risk indexes ( RI) were low and 10. 66% were higher. The contamination level of heavymetals in Yongkang was slight in total, but was heavy in local areas. PMID:27011984

Lead-based coolant reactor is a promising Generation-IV reactor. In the lead-based coolant reactor, the coolant is liquid lead or lead-bismuth eutectic. The main pump in the reactor is a very important device. It supplies force for the coolant circulation. The liquid metal has a very large density which is about ten times of the water. Also, the viscosity of the coolant is small which is about one sixth of the water. When the pump transports heavy liquid, the blade loading is heavy. The large force can cause the failure of the blade when the fatigue stress exceeds the allowable stress. The impeller fraction is a very serious accident which is strictly prohibited in the nuclear reactor. In this paper, the numerical method is used to simulate the flow field of a heavy liquid metal pump. The SST k-w turbulent model is used in the calculation to get a more precise flow structure. The hydraulic force is obtained with the one way fluid solid coupling. The maximum stress in the impeller is analyzed. The stress in the liquid metal pump is compared with that in the water pump. The calculation results show that the maximum stress of the impeller blade increases with increase of flow rate. In the design of the impeller blade thickness, the impeller strength in large operating condition should be considered. The maximum stress of the impeller blade located in the middle and near the hub of the leading edge. In this position, the blade is easy to fracture. The maximum deformation of the impeller firstly increase with increase of flow rate and then decrease with increase of flow rate. The maximum deformation exists in the middle of the leading edge when in small flow rate and in the out radius of the impeller when in large flow rate. Comparing the stress of the impeller when transporting water and LBE, the maximum stress is almost one-tenth of that in the LBE impeller which is the same ratio of the density. The static stress in different medium is proportional to the pressure

This study presents the viability and preference of capacitive deionization (CDI) for removing different heavymetal ions in various conditions. The removal performance and mechanisms of three ions, cadmium (Cd(2+)), lead (Pb(2+)) and chromium (Cr(3+)) were investigated individually and as a mixture under different applied voltages and ion concentrations. It was found that CDI could effectively remove these metals, and the performance was positively correlated with the applied voltage. When 1.2 V was applied into solution containing 0.5mM individual ions, the Cd(2+), Pb(2+), and Cr(3+) removal was 32%, 43%, and 52%, respectively, and the electrosorption played a bigger role in Cd(2+) removal than for the other two ions. Interestingly, while the removal of Pb(2+) and Cr(3+) remained at a similar level of 46% in the mixture of three ions, the Cd(2+) removal significantly decreased to 14%. Similar patterns were observed when 0.05 mM was used to simulate natural contaminated water condition, but the removal efficiencies were much higher, with the removal of Pb(2+), Cr(3+), and Cd(2+) increased to 81%, 78%, and 42%, respectively. The low valence charge and lack of physical sorption of Cd(2+) were believed to be the reason for the removal behavior, and advanced microscopic analysis showed clear deposits of metal ions on the cathode surface after operation. PMID:26476320

Removal of toxic metals and toxins using microbial biomass has been introduced as an inexpensive, new promising method on top of conventional methods for decontamination of food, raw material and concentrated. In this article the potential application of lactic acid bacteria and yeasts as the most familiar probiotics to eliminate, inactivate or reduce bioavailability of contamination in foods and feed has been reviewed. After fast glance to beneficial health effects and preservative properties of lactic acid bacteria, the mechanisms which explain antibacterial and antifungal efficiency as well as their antifungal metabolites are mentioned. Then the article has been focused on potential application of single strain or combination of lactic acid bacteria for removal of heavymetals (copper, lead, cadmium, chromium, arsenic), cyanotoxins (microcystin-LR, -RR, -LF) and mycotoxins (aflatoxin B1, B2, B2a, M1, M2, G1, G2, patulin, ochratoxin A, deoxynivalenol, fumonisin B1 and B2, 3-acetyldeoxynivalenol, deoxynivalenol, fusarenon, nivalenol, diacetoxyscirpenol, HT-2 and T-2 toxin, zearalenone and its derivative, etc) from aqueous solutions in vitro. Wherever possible the mechanism of decontamination and the factors influencing yield of removal are discussed. Some factors which can facilitate metal removal capacity of lactic acid bacteria including the strains, surface charge, pH, temperature, presence of other cations are introduced. The cell wall structure of lactic acid bacteria and yeasts are also introduced for further explanation of mechanism of action in complex binding of probiotic to contaminants and strength of mycotoxin- bacterium interaction. PMID:24329992

In this work, the atmospheric concentrations of selected heavymetals including lead (Pb), iron (Fe), cadmium (Cd), copper (Cu), nickel (Ni), manganese (Mn), and zinc (Zn) were measured for two different sampling sites (urban and rural) in the northern part of Jordan (Irbid city). Samples were collected according to a certain schedule for 1 year. High volume air samplers and glass fiber filters were used to collect the samples. Collected samples were digested using a mixture of analytical grade nitric acid and analytical grade hydrochloric acid, and analyzed to evaluate the levels of heavymetals by atomic absorption spectrophotometry. Six heavymetals (Pb, Fe, Cu, Ni, Mn, and Zn) were measured in all samples; the concentrations of Cd and Co were not detected in Irbid atmosphere by atomic absorption spectroscopy. The results were used to determine the levels of heavymetal pollutants in air, possible sources, and to compare the levels of selected heavymetals in the two studied sites. Aerosols from the rural site have lower concentrations for all the metals compared to those from the urban site. The daily and monthly variations of the elements were investigated. All heavymetals in urban and rural sites reached maximum concentrations in June, July, and August. This is consistent with the increased activities leading to particulate matter emission during the summer period. The enrichment factors with respect to earth crust and correlation coefficients of heavymetals were investigated to predict the possible sources of heavymetals in air. PMID:19083108

Industrial growth, ecological disturbances and agricultural practices have contaminated the soil and water with many harmful compounds, including heavymetals. These heavymetals affect growth and development of plants as well as cause severe human health hazards through food chain contamination. In past, studies have been made to identify biochemical and molecular networks associated with heavymetal toxicity and uptake in plants. Studies suggested that most of the physiological and molecular processes affected by different heavymetals are similar to those affected by other abiotic stresses. To identify common and unique responses by different metals, we have studied biochemical and genome-wide modulation in transcriptome of rice (IR-64 cultivar) root after exposure to cadmium (Cd), arsenate [As(V)], lead (Pb) and chromium [Cr(VI)] in hydroponic condition. We observed that root tissue shows variable responses for antioxidant enzyme system for different heavymetals. Genome-wide expression analysis suggests variable number of genes differentially expressed in root in response to As(V), Cd, Pb and Cr(VI) stresses. In addition to unique genes, each heavymetal modulated expression of a large number of common genes. Study also identified cis-acting regions of the promoters which can be determinants for the modulated expression of the genes in response to different heavymetals. Our study advances understanding related to various processes and networks which might be responsible for heavymetal stresses, accumulation and detoxification. PMID:24553786

Besides organic pollutants, coke production generates emissions of toxic heavymetals. However, intensive studies on heavymetal emissions from the coking industry are still very scarce. The current work focuses on assessing the emission characteristics of heavymetals and their behavior during coking. Simultaneous sampling of coal, coke, residues from air pollution control devices (APCD), effluent from coke quenching, and fly ash from different processes before and after APCD has been performed. The total heavymetal concentration in the flue gas from coke pushing (CP) was significantly higher than that from coal charging (CC) and combustion of coke oven gases (CG). Emission factors of heavymetals for CP and CC were 378.692 and 42.783 μg/kg, respectively. During coking, the heavymetals that were contained in the feedstock coal showed different partitioning patterns. For example, Cu, Zn, As, Pb, and Cr were obviously concentrated in the inlet fly ash compared to the coke; among these metals Cu, As, and Cr were concentrated in the outlet fly ash, whereas Zn and Pb were distributed equally between the outlet fly ash and APCD residue. Ni, Co, Cd, Fe, and V were partitioned equally between the inlet fly ash and the coke. Understanding the behavior of heavymetals during coking processes is helpful for the effective control of these heavymetals and the assessment of the potential impact of their emissions on the environment. PMID:22607524

Based on previous studies and field investigation of Dagang industry area in Tianjin, a total of 128 topsoil samples were collected, and contents of 10 heavymetals (As, Cd, Cr, Co, Cu, Pb, Ni, V, Zn and Hg) were determined. The geoaccumulation index and geostatistics were applied to examine the degree of contamination and spatial distribution of heavymetals in topsoil. The assessment on ecological risk of heavymetals was carried out using Hakanson's method, and the main resources of the heavymetals were analyzed as well. It was found that As, Cd and Co had the highest proportions exceeding Tianjin background value, which were 100%, 97.66% and 96.88%, respectively; the heavy-metal content increased to some extent comparing with that in 2004, and the pollutions of As and Cd were the worst, and other metals were at moderate pollution level or below. The ecological risks of heavymetals were different in topsoil with different land use types, the farmland soil in the southwest as well as soils adjacent to the industrial land were at relatively high potential ecological risk level, and the integrated ecological risk index reached up to 1 437.37. Analysis of correlation and principal component showed that traffic and transportation as well as agricultural activities might be the main resources of heavymetals in the area, besides, the industrial activities in the region might also affect the accumulation of heavymetals. PMID:26911014

The heavymetal contamination in Lake Ohrid, a lake shared between Albania and Macedonia, was studied. Lake Ohrid is believed to be one of the oldest lakes in the world, with a large variety of endemic species. Different anthropogenic pressures, especially heavymetal influxes from mining activities, might have influenced the fragile equilibrium of the lake ecosystem. Heavymetal concentrations in water, sediment, emergent vegetation, and fish were investigated at selected sites of the lake and a study of the heavymetals in five tributaries was conducted. The lake surface water was found to have low levels of heavymetals, but sediments contained very high levels mostly near river mouths and mineral dump areas with concentrations reaching 1,501 mg/kg for Ni, 576 mg/kg for Cr, 116.8 mg/kg for Co and 64.8 g/kg for Fe. Sequential extraction of metals demonstrates that heavymetals in the sediment are mainly present in the residual fraction varying from 75% to 95% in different sites. High heavymetal levels (400 mg/kg Ni, 89 mg/kg Cr, and 39 mg/kg Co) were found in plants (stem of Phragmites australis), but heavymetals could not be detected in fish tissue (gill, muscle, and liver of Salmo letnica and Salmothymus ohridanus). PMID:21541777

We studied atmospheric deposition of heavymetals in Wuxi, China, using moss (Haplocladium microphyllum and H. angustifolium) as a biomonitoring agent. Moss samples were collected from 49 sites determined by a systematic sampling method. The top layer of soil on each site was also sampled. No significant correlation (P heavy metal elements (Cd, Cr, Cu, Ni, Pb, and Zn), indicating that the soil substrate had little effect on the heavymetal concentrations in the moss materials. The metal enrichment capacity of the moss material, characterized by the concentration ratio between the moss and soil samples for each heavymetal, was topped by Cd and then followed by Zn, Pb, Cu, Cr, and Ni, respectively. Significant (P heavy metal pollutants. Based on concentrations of the heavymetals in mosses and the calculated contamination factors, we evaluated the contamination level of each heavymetal on the 49 sampling sites. Spatial distribution maps of heavymetal deposition for each element were interpolated using ArcGIS 9.0. A total pollution coefficient was calculated for each sampling site to identify the seriously polluted areas in the region. PMID:27207630

In Bolivia, metal mining activities since historical times have been one of the most important sources of environmental pollution. This is the case of the National Area of Apolobamba Integrated Management (ANMIN of Apolobamba) in La Paz, Bolivia, where intense gold mining activities have been carried out from former times to the present, with very little gold extraction and very primitive mineral processing technology; in fact, mercury is still being used in the amalgam processes of the gold concentration, which is burned outdoors to recover the gold. Sunchullí is a representative mining district in ANMIN of Apolobamba where mining activity is mainly gold extraction and its water effluents go to the Amazonian basin; in this mining district the productivity of extracted mineral is very low but the processes can result in heavy-metal contamination of the air, water, soils and plants. Due to its high toxicity, the contamination by arsenic and mercury create the most critical environmental problems. In addition, some other heavymetals may also be present such as lead, copper, zinc and cadmium. These heavymetals could be incorporated in the trophic chain, through the flora and the fauna, in their bio-available and soluble forms. Inhabitants of this area consume foodcrops, fish from lakes and rivers and use the waters for the livestock, domestic use, and irrigation. The aim of this work was to evaluate the heavymetals pollution by gold mining activities in Sunchullí area. In Sunchullí two representative zones were distinguished and sampled. Zone near the mining operation site was considered as affected by mineral extraction processes, while far away zones represented the non affected ones by the mining operation. In each zone, 3 plots were established; in each plot, 3 soil sampling points were selected in a random manner and analysed separately. In each sampling point, two samples were taken, one at the surface, from 0-5 cm depth (topsoil), and the other between 5

The technology industrialization was the final goal of the research. A set of automatic line without negative impact to environment for recycling waste printed circuit boards (PCB) in industry-scale was investigated in this study. The independent technologies were integrated and many problems in the process of technology industrialization were solved. The whole technology contained four parts: multiple scarping, material screening, multiple-roll corona electrostatic separator, and dust precipitation. The output of this automatic line reached 600 kg/h and the recovery rate of copper reached 95%. After separation, the metal and nonmetal products were totally reused. Compared with other production lines (traditional fluid bed production line and processing from developed countries), the automatic line has lower energy consumption and better technology rationality. The cost of this line was in acceptable level for local processors. PMID:20092305

The uncontrolled discharges of wastes containing a large quantity of heavymetal create huge economical and healthcare burdens particularly for people living near that area. However, the bioremediation of metal pollutants from wastewater using metal-resistant bacteria is a very important aspect of environmental biotechnology. In this study, 13 heavymetal resistant bacteria were isolated from the wastewater of wadi El Harrach in the east of Algiers and characterized. These include zinc-, lead-, chromium- and cadmium-resistant bacteria. The metal-resistant isolates characterized include both Gram-negative (77%) and Gram-positive (23%) bacteria. The Minimum Inhibitory Concentration (MIC) of wastewater isolates against the four heavymetals was determined in solid media and ranged from 100 to 1,500 μg/ml. All the isolates showed co-resistance to other heavymetals and antibiotic resistance of which 15% were resistant to one antibiotic and 85% were multi- and bi-antibiotics resistant. The zinc-resistant species Micrococcus luteus was the much more heavymetal resistant. The results of toxicity tests on Vibrio fischeri showed that the DI(50) (5 min) as low as 0.1 carried away luminescence inhibition greater than 50%. PMID:22949232

Selecting native plant species with characteristics suitable for extraction of heavymetals may have multiple advantages over non-native plants. Six Australian perennial woody plant species and one willow were grown in a pot trial in heavymetal-contaminated biosolids and a potting mix. The plants were harvested after fourteen months and above-ground parts were analysed for heavymetal concentrations and total metal contents. All native species were capable of growing in biosolids and extracted heavymetals to varying degrees. No single species was able to accumulate heavymetals at particularly high levels and metal extraction depended upon the bioavailability of the metal in the substrate. Metal extraction efficiency was driven by biomass accumulation, with the species extracting the most metals also having the greatest biomass yield. The study demonstrated that Grevillea robusta, Acacia mearnsii, Eucalyptus polybractea, and E. cladocalyx have the greatest potential as phytoextractor species in the remediation of heavymetal-contaminated biosolids. Species survival and growth were the main determinants of metal extraction efficiency and these traits will be important for future screening of native species. PMID:23819263

We analyzed for selenium (Se) and heavymetals in greater scaups (Aythya marila) and surf scoters (Melanitta perspicillata) collected from southern San Francisco Bay in March and April 1982. There were no differences (P > 0.05) between species for liver concentrations of silver (Ag), mercury (Hg), or lead (Pb). Copper (Cu) (P 0.05) between the 2 species. The geometric mean cadmium (Cd) concentration in scoter kidneys (24.6 ppm, dry wt) was higher than in scaups (15.5 ppm) (0.1 > P > 0.05). Liver concentrations of Hg and Se were correlated (P < 0.01). The toxicological significance of some elements in these species is not known. However, Se levels in scoters (34.4 ppm, dry wt) were similar to those in livers of dabbling ducks (Anas spp.) in the nearby San Joaquin Valley where reproduction was impaired severely.

Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavymetals in sewage sludge did meet the requirement the standards of nation.

It is widely accepted that the increased use of antibiotics has resulted in bacteria with developed resistance to such treatments. These organisms are capable of forming multi-protein structures that bridge both the inner and outer membrane to expel diverse toxic compounds directly from the cell. Proteins of the resistance nodulation cell division (RND) superfamily typically assemble as tripartite efflux pumps, composed of an inner membrane transporter, a periplasmic membrane fusion protein, and an outer membrane factor channel protein. These machines are the most powerful antimicrobial efflux machinery available to bacteria. In Escherichia coli, the CusCFBA complex is the only known RND transporter with a specificity for heavymetals, detoxifying both Cu(+) and Ag(+) ions. In this review, we discuss the known structural information for the CusCFBA proteins, with an emphasis on their assembly, interaction, and the relationship between structure and function. PMID:26258953

This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavymetals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1-24h using model solutions (pH 7; 0.1M CaCl2) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P66614][PTB] and 2-(benzylthio)benzoate [P66614][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P66614][BTB] exclusively. PMID:27131456

A novel hydrate-based method is proposed for separating heavymetal ions from aqueous solution. We report the first batch of experiments and removal characteristics in this paper, the effectiveness and feasibility of which are verified by Raman spectroscopy analysis and cross-experiment. 88.01–90.82% of removal efficiencies for Cr3+, Cu2+, Ni2+, and Zn2+ were obtained. Further study showed that higher R141b–effluent volume ratio contributed to higher enrichment factor and yield of dissociated water, while lower R141b–effluent volume ratio resulted in higher removal efficiency. This study provides insights into low-energy, intensive treatment of wastewater. PMID:26887357

Heavymetal fluoride glasses (HMFG) are potentially useful as optical components in a wide range of devices. Their utilization has so far been delayed mainly because of insufficient material purity and inadequate processing conditions. However, as the result of numerous research efforts these problems are gradually diminishing and it now seems likely that the ultimate limitations for use of HMFG components, at least in those applications where high optical transparency is not a prerequisite, will be imposed by more intrinsic instabilities of the glasses themselves. These include their strong tendency to crystallize on quenching and subsequent reheating, low mechanical and chemical durability and the possibility that they will undergo significant physical aging in situ. Experimental data relating to these problems have now been obtained and in the light of these we wish to present an assessment of their relative importance.

The X-Ray, K-Edge HeavyMetal Detection System was designed and built by Ames Laboratory and the Center for Nondestructive Evaluation at Iowa State University. The system uses a C-frame inspection head with an X-ray tube mounted on one side of the frame and an imaging unit and a high purity germanium detector on the other side. the inspection head is portable and can be easily positioned around ventilation ducts and pipes up to 36 inches in diameter. Wide angle and narrow beam X-ray shots are used to identify the type of holdup material and the amount of the contaminant. Precise assay data can be obtained within minutes of the interrogation. A profile of the containerized holdup material and a permanent record of the measurement are immediately available.

This study presents concentrations of heavymetals (iron, zinc, manganese, copper, lead, and cadmium) in livers of three owl species from Korea. Essential trace elements (iron, zinc, manganese, and copper) did not differ among the owl species. We suggest that the essential elements are within the normal range and are maintained by normal homeostatic mechanisms. Lead and cadmium concentrations in Eurasian Eagle Owls (Bubo bubo) were significantly lower than in Brown Hawk Owls (Nixos scutulata) and Collared Scops Owls (Otus lempiji). Lead and cadmium concentrations in Korean owl species were at background levels; lead concentrations in two Collared Scops Owls were above background concentrations. Lead and cadmium concentrations were similar to concentrations previously reported in owls from other parts of the world. We suggest that lead and cadmium concentrations in Korean owls are below toxic concentrations. PMID:17955366

Goat meat farming is increasing in popularity in southeastern region of United States. In order to monitor environmental contamination of heavymetals in goat meat, samples of liver, kidney, and muscle were collected from 20 goats on a goat farm in Notasulga, Alabama. These samples were analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy. The copper concentration was significantly higher in livers than the concentration in kidneys and muscles. Lead, cadmium, and zinc levels did not show any significant differences between liver, kidney, and muscle samples. The concentrations of lead and copper in livers and cadmium in kidneys were significantly different in males when compared to females. However, in muscle, the concentrations of lead, cadmium, copper, and zinc showed no significant difference between male and female or between young and old goats. Further, the concentrations of lead in livers and cadmium in kidneys showed a significant difference between young and old goats.

A prompt gamma ray neutron activation analysis detection system was developed to detect the heavymetals in sediments by using an (241)Am-Be neutron source and BGO detector. The samples containing cadmium and mercury were used to test the performance of setup. The linear relationship between prompt gamma ray counts and the concentrations was studied. The results showed the counts of the prompt gamma rays from cadmium do not increase linearly with its concentrations, while the prompt gamma ray counts from Hg vary nearly linearly with the concentrations, due to the neutron self-shielding. Then a method was used to correct the effect and the non-linearly response was restored after the correction. And the minimum detectable concentration of Cd and Hg were 52.8 (at 8.484MeV) and 81.6 (at 5.967MeV) ppm, respectively. PMID:27015649

This article attempts to determine the resistance of KMTs-R commercial microbead catalyst to poisoning by heavymetals by preparing samples of this catalyst with various contents of nickel. The nickel was deposited by impregnating the catalysts with a benzene solution of nickel naphthenate at the appropriate concentration. It is determined that as the content of nickel in the catalysts is increased, the feedstock conversion, the naphtha yield, and the selectivity for naphtha dropped off monotonically. The effect of antimony diamyldithiocarbamate (compound I) on the poisoning of KMTs-R catalyst by nickel is examined. The results indicate that nickel on the catalyst is passivated by compound I. It is concluded that the parameters of nickel-poisoned KMTs-R catalyst can be restored to a great degree by treatment of the poisoned catalyst with compound I.

Bio-Recovery Systems, Inc. (BRS) studied the application of an immobilized algal biomass, termed AlgaSORB[reg sign], which has high affinity for heavymetal ions to DOE-contaminated groundwaters. The material can be packed into columns similar to commercial ion exchange resins. Dilute solutions containing heavymetals are passed through columns where metals are absorbed by the AlgaSORB[reg sign] resins. Once saturated, metal ions can be stripped from the resin biomass in a highly concentrated solution. Groundwaters contaminated with heavymetal ions from three different Department of Energy (DOE) sites: Savannah River, Hanford and the Oak Ridge Y-12 Plant were studied. The objective was to perform bench-scale treatability studies to establish treatment protocols and to optimize an AlgaSORB[reg sign]/ion exchange technology system to remove and recover toxic metal ions from these contaminated groundwaters. The specialty ion exchange/AlgaSORB[reg sign] resins tested in these studies show promise for selectively removing chromium, mercury and uranium from contaminated groundwater at DOE sites. The data show that effluents which satisfy the allowable metal ion limits are possible and most likely achievable. The use of these highly selective resins also offer advantages in terms of cost/benefit, risk and scheduling. Their high selectivity allows for high capacity and opportunities for recovery of removed constituents due to high pollutant concentration possible (3 to 4 orders of magnitude). Ion exchange is a proven technology which is easily automated and can be cost-effective, depending on the application.

An investigation was carried out to evaluate the effect of heavymetal toxicity on growth, herb, oil yield and quality and metal accumulation in rose scented geranium (Pelargonium graveolens) grown in heavymetal enriched soils. Four heavymetals (Cd, Ni, Cr, and Pb) each at two levels (10 and 20 mg kg-1 soil) were tested on geranium. Results indicated that Cr concentration in soil at 20 mg kg-1 reduced leaves, stem and root yield by 70, 83, and 45%, respectively, over control. Root growth was significantly affected in Cr stressed soil. Nickel, Cr, and Cd concentration and accumulation in plant increased with higher application of these metals. Chromium, nickel and cadmium uptake was observed to be higher in leaves than in stem and roots. Essential oil constituents were generally not significantly affected by heavymetals except Pb at 10 and 20 ppm, which significantly increased the content of citronellol and Ni at 20 ppm increased the content of geraniol. Looking in to the higher accumulation of toxic metals by geranium and the minimal impact of heavymetals on quality of essential oil, geranium can be commercially cultivated in heavymetal polluted soil for production of high value essential oil. PMID:26696243

Fungi represent the main decomposers of woody and herbaceous substrates in the marine ecosystems. To date there is a gap in the knowledge about the global diversity and distribution of fungi in marine habitats. On the basis of their biological diversity and their role in ecosystem processes, marine fungi may be considered one of the most attractive groups of organisms in modern biotechnology, e.g. ecotoxic metal bioaccumulation. Here we report the data about the first mycological survey in the metal contaminated coastal sediments of the Gromolo Bay. The latter is located in Ligurian Sea (Eastern Liguria, Italy) and is characterized by an enrichment of heavymetals due to pollution of Gromolo Torrent by acidic processes that interest Fe-Cu sulphide mine. 24 samples of marine sediments were collected along a linear plot in front of the shoreline in July 2015. Each sample was separated into three aliquot for mineralogical, chemical analyses and fungal characterization. The sediment samples are characterised by clay fractions (illite and chlorite), minerals of ophiolitic rocks (mainly serpentine, pyroxene and plagioclase) and quartz and are enriched some chemical elements of environmental importance (such as Cu, Zn, Pb, Cd, As). For fungal characterisation the sediment samples were inoculated in Petri dishes on different culture media (Malt Extract Agar and Rose Bengal) prepared with sea water and added with antibiotics. The inoculated dishes were incubated at 20°C in the dark for 28 days. Every week fungal growth was monitored counting the number of colonies. Later, the colonies were isolated in axenic culture for further molecular analysis. The mycodiversity evaluate on the basis of Colony Forming Units (CFU) and microfungal-morphotype characterised by macro-and micro-morphology. Until now on the 72 Petri dishes inoculated 112 CFU of filamentous fungi were counted, among these about 50 morphotypes were characterized. The quantitative results show a mean value of 4

The development or implementation of electrokinetic soil remediation technique requires a good knowledge of how the contaminants are retained within the soil-water system. This paper investigates the speciation and extent of migration of the heavymetals, Cr(VI), Cr(III), Ni(II), and Cd(II), during electrokinetic soil remediation. A geochemical assessment of how the contaminants are held within the kaolin soil under induced electric potential is made by using the equilibrium model MINEQL+. The study is performed for three different contaminant cases: the Cr(VI) existing alone in the soil, the Cr(VI) combined with Ni(II) and Cd(II) in the soil, and the Cr(VI) combined with Ni(II) and Cd(II) in the soil in the presence of a reducing agent (sulfide). The adsorption of the studied metals by kaolin was implemented as an electrostatic behavior. FITEQL 4.0 model was used to determine the equilibrium constants of the electrostatic adsorption model of kaolin for the studied metals by optimizing the experimental titration and adsorption data of kaolin. This study showed that the initial speciation of the contaminants in the soil prior to the electrokinetic treatment depends on the type and amounts of contaminants present as well as on the presence of the co-contaminants or any reducing agent. Moreover, the extent of migration of the contaminants is strongly dependent on their initial speciation prior electrokinetic treatment. This study also showed that adsorption and precipitation are the significant hindering mechanisms for the removal of heavymetals from kaolin soil during electrokinetic treatment. The adsorption and precipitation forms of Cr(III), Ni(II), and Cd(II) increased near the cathode and decreased near the anode, whereas the adsorption form of Cr(VI) increased near the anode as well as in the middle region. However, the precipitation form of Cr(III), Ni(II), and Cd(II) as Cr2O3 or Cr(OH)3, Ni(OH)2, and Cd(OH)2, respectively, dominates over their adsorption form

Keywords: anthropogenic effects, land use types, heavymetal content, polluted urban soils, GIS methods Our aim was to identify the main feedback effects between the town and its environment. In the course of our investigation we have analysed the heavymetal contents of urban soil in Sopron town in Hungary. We collected 208 samples on 104 points from 0 to 10 and from 10 to 20 cm depth in a standard network and also at industrial territories. We have been represented our results in a GIS system. We analysed the soils with Lakanen-Erviö method and we measured 24 elements but we have been focused on Co, Cd, Cu, Pb and Zn. Using the data we observed the relationship between these elements in both layers. In the downtown the acidity of soils were alkaline by the greatest number of point, therefore the pollution of these soils is not leach in deeper layers yet. The lead was very high (> 100 mg Pb/kg) in both layers on the whole area of the town. Urban soils with high copper content (among 611 mg and 1221 mg Cu/kg) have been collected from garden and viticulture areas by us. Cadmium contents were the highest (6.14 mg Cd/kg) in traffic zones, where these values could be more than 3 mg Cd/kg according to the literature. The cobalt and zinc results were under the limits. According to our measurements we founded the highest average values in the soils of parks. This could be contamination of the lead from traffic, which bind in the soil of urban green spaces. Now we could continue our examinations with the investigations of these polluted green areas, which can effect to human health.

Contamination of soils with non-degradable heavymetals (HMs) because of human acticities is globally a serious problem threatening human health and ecosystem functioning. To avoid negative effects, HMs must be removed either on-site by plant uptake (phytoremediation) or off-site by extraction (soil washing). In both strategies, HM solubility must be augmented by means of a strong ligand (complexant). Often polycarboxylates such as EDTA and NTA are used but these ligands are toxic, synthetic (non-natural) and may promote HM leaching. Instead naturally occurring soluble humic substances (HS) were tested as means for cleaning HM contaminated soils; HS samples from beech and spruce litter, compost percolate and processed cow slurry were tested. Various long-term HM contaminated soils were extracted with solutions of EDTA, NTA or HS at different pH by single-step and multiple-step extraction mode. The results showed that each of the three complexant types increased HM solubility but the pH-dependent HM extraction efficiency decreased in the order: EDTA ≈ NTA > HS. However, the naturally occurring HS seems suitable for cleaning As, Cd, Cu and Zn contaminated soils both in relation to phytoremediation of moderately contaminated soils and washing of strongly contaminated soils. On the other hand, HS was found unsuited as cleaning agent for Pb polluted calcareous soils. If future field experiments confirm these laboratory results, we have a new cheap and environmentally friendly method for solving a great pollution problem, i.e. cleaning of heavymetal contaminated soils. In addition, humic substances possess additional benefits such as improving soil structure and stimulating microbial activity.

A chronology (1895-present) based on tree-ring increments was constructed for baldcypress (Taxodium distichum L.) trees in Bayou Trepagnier, in southern Louisiana. The best indicator of growth was precipitation in February of the preceding year and October of the 2 previous years. Crossdated cores were used to reconstruct large historical natural environmental perturbations (hurricanes). Heavymetals and organic pollutants from oil refineries and other sources contaminated the bayou commencing in the early 1900s. The Pb and Zn content of 50 trees along Bayou Trepagnier, analyzed in the growth rings of tree cores using x-ray fluorescent spectrometry, produced an historical record of pollution. Highlevels of contamination of Pb, as well as Zn, could be correlated with establishment of petroleum refineries (1916) and dredging (1930-1950) of the area, which created spoil banks containing high levels (ca. 300-1600 mg/kg [ppm] Pb) of heavymetals. Concentrations of Pb, per tree, ranged form 0.6 to 14 mg/kg (ppm). Trees in the upper protion of the bayou (near the refiney) contained an average of 4.5 mg/kg (ppm) Pb; trees in the lower portion averaged 2.2 mg/kg (ppm). Concentrations of Zn per tree ranged from 1.7 to 14.8 mg/kg (ppm), but in contrast with Pb did not correlate with distance from pollution sources; trees averaged 5.5 and 5.4 mg/kg (ppm) Zn in the upper and lower portions, respectively, of Bayou Trepagnier. Levels of Pb and Zn in a control ecosystem, Stinking Bayou, were 1.0 and 5.2 mg/kg (ppm), respectively. 39 refs., 7 figs., 2 tabs.

Structural studies were performed on several proteins of the bacterial detoxification system. These proteins are responsible for binding (MerP) and transport of heavymetals, including mercury, across membranes. The structural information obtained from NMR experiments provides insight into the selectivity and sequestration processes towards heavymetal toxins.

The study´s background is the estimation of the status quo of heavymetal emissions into the river systems of Baden-Wuerttemberg, which is essential for the implemetation of the European Water Framework Directive. Therefore the input of seven heavymetals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) into the river systems of Baden-Wuerttemberg via various point and diffuse pathways is estimated. The use of this data will enable us to identify significant sources and pathways which will help to decrease heavymetal emissions. For the quantification of emissions from point sources, data is taken from surveys on municipal wastewater treatment plants, industrial direct discharges, and historic mines. The input from diffuse sources is calculated using an adapted version of the model MONERIS (Behrendt et al. 2000). This model accounts for the significant transport processes and includes a Geographical Information System (GIS) that provides digital maps as well as extensive statistical information. For the comparison of the calculated heavymetal emission, and the heavymetal load measured at monitoring stations, the loss of heavymetals due to retention processes within the river system are calculated according to the retention functions given by Vink &Behrendt (2002). Today's emissions of heavymetals into the river systems of Baden-Wuerttemberg are dominated by the input from diffuse sources, e.g. paved urban areas and erosion. For different types of heavymetals different sources and pathways play an important role.

The difference in the accumulation rate of a mixture of heavymetals in aquatic organisms is of considerable interest because of its importance in the prediction of the effect of pollutants in aquatic systems. In this study the authors are making an effort to evaluate the accumulation patterns of pollutants in aquatic organisms by establishing a relation between the level of an accumulated mixture of heavymetals (Cd, Zn, Pb, As, Hg) in individuals of Daphnia magna, Daphnia pulicaria and Daphnia galeata and its dry weight with respect to the form of heavymetals in the aquatic environment. One age group of Daphnia species (10 day old) were exposed to 5 ppb, 10 ppb and 20 ppb of the mixture of heavymetals for 24 hours in three different experiments. In the first experiment the mixture of heavymetals was present exclusively in labelled algae (Scendesmus actus), in the second in an aquatic medium with non labelled algae, and in the third experiment the mixture of heavymetals was dissolved in the aquatic medium only without the addition of algae. The concentration of the heavymetal mixture in individuals of D.magna; D.pulicaria and D.galeata was determined using atomic absorption spectrometry. Results were statistically evaluated and the rate of accumulation and influence of various heavymetals in the biomass of three Daphnia species is discussed.

The investigations of heavymetal (Ni, Cu, Co, Zn, Pb, Cd, Hg) distribution in sediments of more than 100 lakes were carried out between 1989 and 1994. The study lakes are situated at different distances from two main heavymetal pollution sources of the Kola Peninsula-smelters of the Pechenganickel and Severonickel Companies. To assess the pollution extent of investigated lakes, values of factor and degree of contamination were calculated according to the method suggested by Hakanson (1980). Heavymetal contamination factor (C{sub f}) for each heavymetal was calculated as the quotient of concentration from the uppermost (0-1 cm) sediment to the mean preindustrial background value (concentrations from 20-30 cm sediment layers) for the investigated region. Degree of contamination (C{sub d}) was defined as the sum of all contamination factors for studied heavymetals. To quantitatively express the potential ecological risk of given contaminants created for ecosystems, risk factor (Er) for each heavymetal has been calculated. Er takes into account the toxicity of a heavymetal and bioproduction index (BPI) of a lake. Risk index (RI) was determined as the sum of all ecological risk factor for studied heavymetals.

This article reviews the experimental data on heavymetals in the aquatic environment and their biological effects on aquatic ecosystems. Arsenic, cadmium, copper, chromium, lead, mercury, zinc, selenium, and cobalt were discussed. In addition, the concepts of bioconcentration and detoxification of heavymetals were described. (KRM)

Heavymetal pollution in soils, sediments and wastewater poses a significant environmental and public health threat due to toxicity and the potential for bioaccumulation in both plant and animal tissues. Remediation of heavymetals in soils and sediments using solely physical or...

Heavymetal pollution in soils, sediments and wastewater poses a significant environmental and public health threat due to toxicity and the potential for bioaccumulation in both plant and animal tissues. Remediation of heavymetals in soils and sediments using solely physical or...

The hot-acid method for treating sludge was developed by the Walden Division of Abcor, Inc., to remove heavymetals from municipal wastewater sludge. Investigations by Walden have demonstrated the degrees to which heavymetals are solubilized. Sulfuric acid dosage at about 20 to ...

Heavymetals build-up on urban road surfaces is a complex process and influenced by a diverse range of factors. Although numerous research studies have been conducted in the area of heavymetals build-up, limited research has been undertaken to rank these factors in terms of their influence on the build-up process. This results in limitations in the identification of the most critical factor/s for accurately estimating heavymetal loads and for designing effective stormwater treatment measures. The research study undertook an in-depth analysis of the factors which influence heavymetals build-up based on data generated from a number of different geographical locations around the world. Traffic volume was found to be the highest ranked factor in terms of influencing heavymetals build-up while land use was ranked the second. Proximity to arterial roads, antecedent dry days and road surface roughness has a relatively lower ranking. Furthermore, the study outcomes advances the conceptual understanding of heavymetals build-up based on the finding that with increasing traffic volume, total heavymetal build-up load increases while the variability decreases. The outcomes from this research study are expected to contribute to more accurate estimation of heavymetals build-up loads leading to more effective stormwater treatment design. PMID:26897571

With the rapid development of society, more and more attention has been focused on environmental safety, especially on the pollutions of heavymetals, pesticides, persistent organic pollutants and deleterious microorganism. Heavymetals are difficult to metabolize in human body are quite harmful, so research on the pollution of heavymetals is increasingly important. There are many pollution sources of heavymetals, including waste residue, waste water and exhaust gas from industry and automobile, and garbage from human life. The contents of 10 kinds of heavymetals (Cr, Ni, Cu, As, Cd, Sn, Sb, Hg, Tl and Pb) in potassium fertilizer (KCl) from Russia were analyzed by ICP-MS. The results showed that potassium fertilizer (KCl) contained less heavymetals than organic-inorganic compound fertilizer; the content of heavymetals Cr, Ni, Cu, As, Cd, Sn, Sb, Hg, Tl and Pb is 0.00, 65.54, 238.85, 190.60, 0.98, 14.98, 2.97, 10.04, 1.28 and 97.42 ng x g(-1), respectively, which accords with the correlative standards. All the data showed that if potassium fertilizer (KCl) is manufactured through normal channel, the content of heavymetals should be little and safe. PMID:19123423

College students are typically very identified with popular music and spend many hours listening to their music of preference. To investigate the effects of heavymetal music, we compared the responses of 18 female undergraduate college students to a baseline silence condition (A) and a heavymetal music condition (B). Dependent measures included:…